Yeah, rsync.net is pricey, but in reliable.
I been using Interserver[1] + borg[2] for the last 3 years. With the 10TB plan comes out to $25/mo, but if you prepay a year there's discounts.
For the OPs use case, they have a 40TB plan for $84/mo. Still pricey, but, cheap compared to most other cloud storages. If you have data you care about, off-site backups are required.
[1] https://www.interserver.net/storage/
[2] https://borgbackup.readthedocs.io/en/stable/