I use mostly Apple products/services to include iCloud+, Private Relay, and Advanced Data Protection (their E2EE cloud service).
However I keep email and password manager strategically separated. Bitwarden for password management and Proton for email (and VPN). This ensures some redundancy in accounts. If for some reason my Apple account was locked/lost access I would still have email and passwords for other accounts plus local backups of my data. Also if somehow my Proton account was breached the attacker would not have access to my Apple cloud data nor my passwords.
Even if Protonpass or Proton Drive ever reached feature parity with iCloud and Bitwarden I would not go ‘all in’ on Proton due to the need to strategically diversify critical accounts. Any of these services could disappear or lock you out for reasons outside your control (service disruptions, mistaken accusation of service term violations, etc). If you are ‘all in’ on only one you are really screwed.
Same reason it is critical to keep local backups of all your data in addition to a cloud service. If Apple ever got mad at me and locked me out of my Apple account I would still have local copies of all my data.