If you own your own domain the you can use a paid tier of a service like Proton or Tuta where the emal is you@yourdomain.tld and the backend is actually them, so you don't need to selfhost.
Tuta's nice (Germany), the only think Proton (Switzerland) as over it - for me - is an .onion site, although they leak a lot of links onto clearweb. I've heard of Fastmail but haven't tried it.
Linux does have proprietary blobs, Canonical has signed some NDAs, so not that far off from Android (which is linux-based and certainly has proprietary firmware).
Guess you'd have to be a smart scumbag too...