I'm also sick of hearing about Swiss privacy laws. Their intelligence service got busted covering for a US and German spy front operation in Switzerland. If it happened once, I promise it has happened before and since.
Edit for those who can't click: a front company in Switzerland sold fake encrypted communications services around the world for years, possibly decades, with the assistance of Swiss intelligence agencies.
Self hosted email is its own can of worms. I wouldn't recommend it to anyone outside of experienced IT people. You'll end up blacklisted before you send your first email if you do anything wrong (and there's a lot that can go wrong), and it doesn't solve any security problems email has.
Anything sent over email just isn't private. That goes for Proton customers when they send or receive anything from a non-Proton address too. The one thing privacy email providers can actually do is keep your inbox from being scanned by LLMs and advertisers. That doesn't prevent the inboxes and outboxes of your contacts from being scanned, though.
If you use email, the best thing you can do is be mindful of what kinds of information you send through it. Use aliases via services like simple login or anonaddy when possible. Having a leaked email is a security vulnerability. Once bad actors have your email, they now have half of what they need to breach multiple accounts.