Looks like that might be changing https://www.gsma.com/newsroom/article/rcs-encryption-a-leap-towards-secure-and-interoperable-messaging/

It really is a shame that it looks so terrible. It’s a really solid office suite otherwise, but I agree that it’s not a pleasure to use simply because of how ugly it is

I’m also looking to migrate and was recommended this service when I asked a similar question to OP. https://www.migadu.com/index.html

Unlimited inboxes. You’re just limited to inbox space, but you can have multiple domains.

I’ll be moving over to them when my current subscription runs out with my current provider

SSH is the answer.

Another approach would be to use WSL (windows subsystem for linux) and basically just communicate from one Linus box to another

Can you share where to find the android app? I can’t see it in the play store or fdroid