If you’re tech savvy and want to save a few bucks by doing it yourself, check out borg[2]. You’ll need to set up an external server for it but at scale (TB) it’s an order of magnitude cheaper than Tarsnap.
Regardless of off site storage I’d suggest also buying two large USB drives and formatting them with LUKS. Keep them offline and only sync them occasionally as live storage isn’t really a backup.
If you’re not tech savvy I’m convinced what you’re asking for is impossible. The best a layman can do is pick a reputable provider (like the ones you’ve listed).