I've been using Protonmail with 3 custom domains for a few years, but I'm quite upset by the state of their bridge. They struggled a lot with IMAP compatibility

I've been using Protonmail with 3 custom domains for a few years, but I'm quite upset by the state of their bridge. They struggled a lot with IMAP compatibility, they only test it on Thunderbird, Outlook and Apple Mail before releasing it, and you can't connect to the bridge from another machine (well, you can technically set up an SSH tunnel or use socat to forward the localhost ports, but that's a hack that is not officially supported nor advised). I'm now considering switching to Fastmail or Tutanota. Or even run my own mail server. I used to do that until a couple of years ago, but I eventually got frustrated by all the dumb rules that Google and Microsoft (but mostly Microsoft) set in place to discourage people from running their own servers. However, given the amount of time that I've already spent to debug the Proton bridge and open PRs to fix their sh*t, I must acknowledge that running my own Postfix server and spending a couple of hours to set up the right DNS records would have probably saved me a lot of time (and money).