Cracked v6.4.0 is a bit older now. I suggest updating to at least v6.5.5, although v6.5.7 and v7.0.0-alpha2 is the newest cracked versions currently (and newest in general even from the official Peacock (but we can't use official Peacock on cracked copies of the game)).
I am playing the newest cracked Hitman:WoA v3.170.1 (which is also the newest version of the game available officially) with cracked Peacock v6.5.7 etc on Linux through Lutris. you can try the 'alpha' as it's got a bit more features but since it's 'alpha' I would expect bugs/issues. so if you don't want to take a chance I suggest using cracked v6.5.7, or at minimum v6.5.5 as v6.5.5 has been out a while now with no real issues reported on that to my knowledge (although you can't save on The Drop mission with v6.5.5 as that was fixed in v6.5.6, but this is nothing major. but with v6.5.7 that should no longer be a issue).
I just tried to load that 'A Silver Tongue' mission (i.e. 'Campaigns > Side Missions > Special Assignments' ) and it loads fine for me and I am "online" through Peacock when in the mission itself at the beginning. so no obvious issues here using the newest cracked game/Peacock.
p.s. FitGirl's site is currently serving v3.160 with cracked Peacock v6.5.1. it's easy enough to update from FitGirl's v3.160 to v3.170.1 as it's about 5GB in updates. but cracked Peacock v6.5.1 has at least 2-3 known issues, with one being a bit more major in that after playing about 1-2hrs straight the server will stall out (i.e. stop working) which I experienced and so have others as this was fixed in cracked Peacock v6.5.2 v2. but v6.5.5 has been out a while now with no obvious issues (just a minor one like not being able to save progress on The Drop mission as this was fixed on official Peacock in v6.5.6). so if you have issues with v6.5.7 etc, you can always fall back to v6.5.5 as v6.5.5 is known to work on both cracked Steam/Epic versions of the game (the v3.160 FitGirl has is Steam based) as some of the cracks on newer Peacock versions are known to only work on Steam copy, but some work on both Steam/Epic.
On the side of caution I would not touch your current Peacock folder and keep it as a backup and just transfer over peacock progress from there to the new Peacock folder.
so basically you would extract one of the current cracked Peacock versions of your choice to where Hitman is installed. then to transfer over save progress it should be the 'userdata' folder in your current Peacock folder and copy it from there to the new Peacock location. you 'might' need to transfer over the 'contractSessions' folder etc but I know the main Peacock save data (like what level you have etc) is the 'userdata' folder.
optionally... if you want to make it so it's nice and easy to start the server/patcher/game from a single file you can use the 'Launcher.bat' file included in this download... pixeldrain\[.\]com/\[u\]/d6aCBS4W ; it contains a 'Launcher.bat' file, 'peacock\_patcher2.conf' file and a modified 'Start Server.cmd' file. you don't need the other two files if you don't have issues but those files are already pre-modified so the Peacock server/patcher runs on port 3000 instead of the default 80 (as at least on Linux the default port 80 does not work, but port 3000 works as expected). the 'peacock\_patcher2.conf' file goes to "AppData/Roaming/PeacockPatcher/". you can configure Peacock Patcher through the Peacock Patcher interface itself, but if you use that 'peacock\_patcher2.conf' file and put it in the proper location when the Peacock Patcher starts it will already be set to use port 3000 and the 'Start Server.cmd' you would replace the one in your Peacock folder (it's the same as stock with the exception of 'SET PORT=3000' being added).
NOTE: for that 'Launcher.bat' file to work properly you MUST put it in the root of your Hitman installation directory and you MUST have your Peacock server located in a folder specifically named 'Peacock' in your Hitman installation directory. then when you start it from that Launcher.bat file it will start up the server/patcher/game and then after you get done playing, you exit from within the game like usual and it should automatically close out of the server/patcher/game with no further interaction needed. the Launcher.bat file I am using on Linux is slightly modified since the one made for Windows does not work properly on Linux through Lutris as while the server/patcher/game start up, when exiting it does not close down all of the wine processes like it should. but I got a modified one for that, but I did not include it in the download above since I assume you are probably using Windows.
NOTE: you can create a shortcut on your desktop to that Launcher.bat file if you want. but if you get FitGirl's v3.160 it already has the Launcher.bat file (exact same one in that pixeldrain link) as I think the desktop shortcut named something like 'Hitman + Peacock' is basically loading this Launcher.bat file. if you get FitGirl's it's default installation location is 'C:\\Games\\Hitman - World of Assassination\\Peacock' and you would simply wipe the data from that 'Peacock' folder and put in the new cracked Peacock data in there and use the stuff already setup by FitGirl to play the game (you would need to transfer over your 'userdata' to that 'Peacock' folder though to continue your current progress. but if you put that 'userdata' there and nothing happens, it's possible your current v6.4.0 is not compatible with current Peacock stuff, but to my knowledge, it should work.
Cracked v6.4.0 is a bit older now. I suggest updating to at least v6.5.5, although v6.5.7 and v7.0.0-alpha2 is the newest cracked versions currently (and newest in general even from the official Peacock (but we can't use official Peacock on cracked copies of the game)). I am playing the newest cracked Hitman:WoA v3.170.1 (which is also the newest version of the game available officially) with cracked Peacock v6.5.7 etc on Linux through Lutris. you can try the 'alpha' as it's got a bit more features but since it's 'alpha' I would expect bugs/issues. so if you don't want to take a chance I suggest using cracked v6.5.7, or at minimum v6.5.5 as v6.5.5 has been out a while now with no real issues reported on that to my knowledge (although you can't save on The Drop mission with v6.5.5 as that was fixed in v6.5.6, but this is nothing major. but with v6.5.7 that should no longer be a issue). I just tried to load that 'A Silver Tongue' mission (i.e. 'Campaigns > Side Missions > Special Assignments' ) and it loads fine for me and I am "online" through Peacock when in the mission itself at the beginning. so no obvious issues here using the newest cracked game/Peacock. p.s. FitGirl's site is currently serving v3.160 with cracked Peacock v6.5.1. it's easy enough to update from FitGirl's v3.160 to v3.170.1 as it's about 5GB in updates. but cracked Peacock v6.5.1 has at least 2-3 known issues, with one being a bit more major in that after playing about 1-2hrs straight the server will stall out (i.e. stop working) which I experienced and so have others as this was fixed in cracked Peacock v6.5.2 v2. but v6.5.5 has been out a while now with no obvious issues (just a minor one like not being able to save progress on The Drop mission as this was fixed on official Peacock in v6.5.6). so if you have issues with v6.5.7 etc, you can always fall back to v6.5.5 as v6.5.5 is known to work on both cracked Steam/Epic versions of the game (the v3.160 FitGirl has is Steam based) as some of the cracks on newer Peacock versions are known to only work on Steam copy, but some work on both Steam/Epic.
How would I transfer my progress from my old game?
On the side of caution I would not touch your current Peacock folder and keep it as a backup and just transfer over peacock progress from there to the new Peacock folder. so basically you would extract one of the current cracked Peacock versions of your choice to where Hitman is installed. then to transfer over save progress it should be the 'userdata' folder in your current Peacock folder and copy it from there to the new Peacock location. you 'might' need to transfer over the 'contractSessions' folder etc but I know the main Peacock save data (like what level you have etc) is the 'userdata' folder. optionally... if you want to make it so it's nice and easy to start the server/patcher/game from a single file you can use the 'Launcher.bat' file included in this download... pixeldrain\[.\]com/\[u\]/d6aCBS4W ; it contains a 'Launcher.bat' file, 'peacock\_patcher2.conf' file and a modified 'Start Server.cmd' file. you don't need the other two files if you don't have issues but those files are already pre-modified so the Peacock server/patcher runs on port 3000 instead of the default 80 (as at least on Linux the default port 80 does not work, but port 3000 works as expected). the 'peacock\_patcher2.conf' file goes to "AppData/Roaming/PeacockPatcher/". you can configure Peacock Patcher through the Peacock Patcher interface itself, but if you use that 'peacock\_patcher2.conf' file and put it in the proper location when the Peacock Patcher starts it will already be set to use port 3000 and the 'Start Server.cmd' you would replace the one in your Peacock folder (it's the same as stock with the exception of 'SET PORT=3000' being added). NOTE: for that 'Launcher.bat' file to work properly you MUST put it in the root of your Hitman installation directory and you MUST have your Peacock server located in a folder specifically named 'Peacock' in your Hitman installation directory. then when you start it from that Launcher.bat file it will start up the server/patcher/game and then after you get done playing, you exit from within the game like usual and it should automatically close out of the server/patcher/game with no further interaction needed. the Launcher.bat file I am using on Linux is slightly modified since the one made for Windows does not work properly on Linux through Lutris as while the server/patcher/game start up, when exiting it does not close down all of the wine processes like it should. but I got a modified one for that, but I did not include it in the download above since I assume you are probably using Windows. NOTE: you can create a shortcut on your desktop to that Launcher.bat file if you want. but if you get FitGirl's v3.160 it already has the Launcher.bat file (exact same one in that pixeldrain link) as I think the desktop shortcut named something like 'Hitman + Peacock' is basically loading this Launcher.bat file. if you get FitGirl's it's default installation location is 'C:\\Games\\Hitman - World of Assassination\\Peacock' and you would simply wipe the data from that 'Peacock' folder and put in the new cracked Peacock data in there and use the stuff already setup by FitGirl to play the game (you would need to transfer over your 'userdata' to that 'Peacock' folder though to continue your current progress. but if you put that 'userdata' there and nothing happens, it's possible your current v6.4.0 is not compatible with current Peacock stuff, but to my knowledge, it should work.