Gnome evolution works great; I've used it with everything you are talking about except ProtonMail.
It defaults to the bizarre Gnome look (no native controls, toolbar buttons haphazardly strewn through the title bar), but you can change it in the preferences if you hate that as much as I do.
I have a relatively niche use case where thunderbird would no longer find my smime certificate on my smart card. But only in the compose/send UI, not in settings.
While I understand not many people are doing this, it also... Used to work, and I would have thought that detecting regressions in X.509 cert validation should be well covered by tests.
I ended up having to switch ti Thunderbird because my work email turned off its imap connector and evolution didn't support the exchange 2fa they are using. Maybe it's supported now? I did prefer evolution to Thunderbird. .
I think I tried this but it wasn't supported by our Exchange setup for whatever reason that I can't remember. I might try again at some point though...
Another option to try is davmail; it exports davmail/caldav/carddav/LDAP from an exchange server.
My only note with that is the caldav and exchanges internal handling of event invites will fight with each other, so don't try to accept invites from within your imap mail client.
It defaults to the bizarre Gnome look (no native controls, toolbar buttons haphazardly strewn through the title bar), but you can change it in the preferences if you hate that as much as I do.