What are you using now? Asking for a friend
I use rsync.net. You can use basically any SSH tool or rclone interface. They have a cheaper plan for "experts" if you want to forgo zfs snapshots,https://www.rsync.net/signup/order.html?code=experts.
I have used Arq for way over a decade. It does incremental encrypted backups and supports a lot of storage providers. Also supports S3 object lock (to protect against ransomware). It’s awesome!
Wasabi + rclone works well for me. Previous BB customer.
Not OP, but I have been using borg backup [1] against Hetzner Storage Box [2]
Borg backup is a good tool in my opinion and has everything that I need (deduplication, compression, mountable snapshot.
Hetzner Storage Box is nothing fancy but good enough for a backup and is sensibly cheaper for the alternatives (I pay about 10 eur/month for 5TB of storage)
Before that I was using s3cmd [3] to backup on a S3 bucket.
[1] https://www.borgbackup.org/
[2] https://s3tools.org/s3cmd
[3] https://s3tools.org/s3cmd