@makuharigaijin Here is a tip, never trust your data on someone elses cloud/server, in other words i'd say no.
If self hosting stuff isn't an easy access thing for you, then simply just get a safe USB/Hard drive to store all your information on. Encrypting that info is always great to.
@glitcher32 I already run my own mail services, Nextcloud, etc., but have not found a project for selfhosting FF syncing that looks active. Do you know of one?