I absolutely know people who not use it in good faith. Same people that crammed many terabytes into Amazon Drive back when it was unlimited so that they could "back up their plex server".
So what is the best off-site solution for backing up a NAS in good faith? I have about 10TB of data that is "backed up" to varying degrees but no all-in-one solution right now.
Assuming that your NAS is Linux-based, maybe Borg with Rsync.net may suit you (used it for mine, satisfied with it). Note that you are responsible for keeping the Borg encryption keys if you used it. $80/month (for 10 TB) might be yikes though if you're expecting a web or mobile-browsable backup though (since Rsync.net is literally a ssh storage provider), and if you want to keep snapshots, you need to also pay for their storage. Borg supports FUSE access though, so if you really need to browse then that should be good enough for occasional one-off restores.
rclone with anything that's paid per tb, e.g. Amazon S3/Glacier or Backblaze B2. Data storage (and retrieval!) isn't cheap, however, and the pricing isn't simple.
You can back up 10 TB of data to a single external hard drive these days. Making it "offsite" is as simple as taking it to a secondary location (office, family, etc.). Your one-time cost is higher, but there's no ongoing monthly fee.