I don't understand why you don't blame Apple first of all for their methods of locking up open standards and/or modifying them just enough that non-apple products won't work.
I don't support Chinese companies for doing shitty products, but fuck Apple for everything they do to lock you in their "ecosystem."
You don't have 100% privacy as long as you send mails to people and services that don't support proton's encryption. If I wasn't privacy I can always use gpg.
Yes, and both have proprietary clients. I have proton and I'm in the process to moving away mainly because I can't use their calendar and contacts natively in Android. Not sure about Tuta, but I never liked them.
I think you remember something that is 15 years old. Samsungs are very good now and even though I don't use the default launcher (OneUI), when I used it it didn't seem clunky or anything. And yes, they put a lot of junk apps by default, but you can uninstall most of them right off the bat and never care.