Regardless of service, if you don't test your backups, you have none.

I use Duplicati connected to Storj with data volumes that incrementally get backed up once per month. My files don't change very often, so monthly is a good balance. Not counting my Jellyfin library, those backups are around 1 TB. With the Jellyfin library, almost 15 TB.

Earlier this year, I recovered from a 100% data loss scenario, as I didn't (and still don't) have space for physical backups. I have a 25 TB allowance, so my actual cost was €0. If I had to pay, it would have been under €1.