I bounced around a bit after Storj decided to hate consumers and institute massive minimums.

I've landed on Backblaze B2, S3 compatible. Add others have mentioned, doing a shared NAS 2 NAS hookup with a friend or family member is a nice ideal way to do it without monthly fees.

I use Borg backup from my PCs to a NAS (QNAP), and from there using the built in backup software to go off-site. My self hosted PCs will mount NAS drives directly (like immich and audiobookshelf) and those are also in the NAS off-site job.