I love Proton and will advocate for it any chance I get, but I can also see that it might be good to have people like you who don't put all their eggs in one basket
I degoogled to Proton mail initially. I didn't like that I couldn't search my emails (a security thing or something? But annoying) and then their Drive was absolutely useless on macos. I had about 100gb and it couldn't sync even half of it.
After much help from support I eventually moved away to a combo of Fastmail, Mega and OnlyOffice.
I did the same thing. The first privacy-oriented service I heard about was Proton. And, to be fair, they're quite good. But the email search issues and struggles I had with their bridge eventually turned me off.
I left for mailbox(.)org and haven't looked back. It's great Proton has so many cool services, but the last thing I want is to get dependent on one company again, not after how hard it was to get away from Google.