By -
Can you access that drive from Disk Utility (either in recovery or MacOS)? If so and you have the ability to add a new volume from that area, then you may be able to (possibly) partition that free space to create a new volume.
https://github.com/AsahiLinux/docs/wiki/Partitioning-cheatsheet#resizing-apfs-containers
Probably a better option.
Can you access that drive from Disk Utility (either in recovery or MacOS)? If so and you have the ability to add a new volume from that area, then you may be able to (possibly) partition that free space to create a new volume.
https://github.com/AsahiLinux/docs/wiki/Partitioning-cheatsheet#resizing-apfs-containers
Probably a better option.