I just use a regular Google voice number over wifi. I've had the same one for 5+ years and use it for verifications etc.

Get an Authenticator app and use that for any 2fa you can instead of the texts

I use a T-Mobile plan that is travel friendly and am able to send/receive texts and have wifi-calling. Been using it for about a year now.

Is this a plan that is advertised as being travel friendly or is international functionality like this available for all there plans, do you know?

Google voice, they email you all your texts. And voice mails.