It might not have the functionality you are looking for as far as app integrations, but my progression was Dropbox -> Cryptomator over Dropbox -> rclone over Backblaze B2.
You can nest a "crypt" remote (end-to-end encryption with your own private key) over tons of cloud providers. You can mount it like a drive in Linux.
Round Sync is an Android client that can schedule cronlike backups. Pretty much set it and forget it on my phone. I delete things on my phone when I need space and every couple years go cleanup what's in B2.
Dropbox was better priced at max capacity when I used it ($120/yr for 2TB?). My Backblaze bill started at $1/mo and is like $4/mo now. Its been a couple years since I cleaned things out and could probably cut that in half.