Uh, just tried to install Stalwart, the Rust mailserver suite. It’s nice. But you have to switch to nixos-unstable to get some important features as of now. And then I can’t find any resources on how to set it up. Meaning there are no sane defaults floating around on the internet and it’s really a chore to learn the internals and come up with a proper config. Maybe the nix-mailserver is a better choice for now.
https://wiki.postmarketos.org/wiki/Devices
If you want Linux on your phone. But Android is probably easier to use. Something like LineageOS or /e/ works pretty well. I’m not sure what kind of phone to recommend for that.