The solution should not be one single provider. Use Ente for pictures, maybe Proton* for other cloud storage and Docs replacement, look into a Nextcloud server hosted by another provider for calendar and email. Don't put all your digital eggs in one walled nest.
*Proton is plagued by a CEO who can't keep his mouth shut about politics. Look into that and how you feel about it before you sign up. Their VPN is good but I wouldn't use them also for email to make switching less of a headache - and I don't think you could use your own domain there anyway.
Security is one thing. I was more thinking about the pain of having to move everything again when the single provider goes bankrupt or becomes politically intolerable or gets swallowed by the kraken.