My experience with Proton was not great. I signed up, with the intention of switching. Had some IRL stuff come up, so while I was using it, I hadn't migrated everything and it was a good thing I didn't. I had a password issue. I couldn't sign in. I admit, I should have setup the recovery email, but I'm a dumbass.
So, I opened a ticket, and in the end, they couldn't help me. Even though I had the recovery phrase (which didn't work), and I had the email verification they sent me with the date, time and header info showing it came from them to me, and the mail ID. Even though I had that, they wouldn't consider it proof that I setup the account and wouldn't recover it for me.
And because they won't reuse email addresses, I lost my email address.
To me, the only part that was my fault was not setting up a recovery email. I still have my username and password in my password manager. But not being able to recover it, when it just stopped working, and I couldn't get my account back, is on them.