I use Backblaze B2 through my Synology NAS to offsite my important data. Most things though I just backup locally and accept the risk of needing to rebuild certain things (like most of my movie/TV media files since I can just re-rip my physical media, and the storage costs are not worth the couple of days of time in that unlikely case).
I really think this is key when thinking about your backup strategy that is specific to self hosting compared to enterprise operations. The costs come out of our pockets with no revenue to back it up. Managing backups for self hosting IMO is just as much about understanding your risk appetite and then choosing a strategy to match that. For example I keep just single copy in B2, since the failure mode I’m looking to protect against is catastrophic failure of my NAS which holds my main backups and media. I then use Proton Drive and OneDrive to backup secrets for my 2FA setups and encryption for my B2 bucket. This isn’t how I would do it at work (we have a fair more robust, but much more expensive setup). But my costs for B2 are around $15/mo which I am fine with. When I tried keeping multiple copies it had grown to over $50/mo before I cared enough to really rethink things (the cost of the hobby I told myself).
So paperless works as a service that ties into your storage. I point mine at an NFS share on my Synology and just backup that share. The documents are all stored as PDFs still so worst case I still have “dumb” copies without all the tagging available if my paperless instance goes offline for some reason.