These days I use Btrfs snapshots to do incremental backups to an external drive each week, it's manual but it takes less than 5 minutes a week, the most I risk losing is a week of data and I trust it a lot more than relying on some external service that might go down at any time or randomly decide to delete my account. For most people just worried about photos I would assume that's enough, I feel like anything else is just over-engineered.