I had backblaze, and it’s really a bummer they don’t support linux. The closest one I’ve found is Icedrive, but it costs a bit more. I don’t mind paying a bit more though for a FOSS solution (technially not free but yeah). I probably only have 2 TB of actual important stuff but it would be nice to have more for future.
I use Nextcloud with Hetzner Storage Share. Quite cheep, and easy to synch two PCs and a phone. I also use another old PC where I sync to every week to have a ‘local’ backup.