And that proves what exactly? Swiss law required them to hand over an IP address. Swiss ptivacy is not absolute. They have laws. An IP address didn't grant them access to the encrypted emails. Proton openly admits they had no idea who the user was. The activist should have used a VPN, which Proton also offers as a service, and then whatever activity trail they linked to the IP would have died at Proton's VPN network.
Five and eleven eyes doesn't matter if the service is encrypted and open sourced. Also, did you know that Switzerland has no superior privacy laws comparing to Germany? It's all marketing bluff.
I self-host (postfix and dovecot) and will admit of all the self-hosted stuff I have it's the most annoying/time-consuming to manage but doable if you're willing to spend a lot of time reading and updating things. I wouldn't recommend it to the vast majority of people though.
I read some horror stories about folks who self-hosted for years and how they eventually quit and moved to an established email provider. It didn't seem like something I wanted to deal with.
Do you think using one of those federated email networks where it's invite only and between people you know would have any appreciable use cases in conjunction with an established provider? I can think of having a small org use it maybe but not between friends or family.