My server doesn't have a lot of storage, so I can only have like around 10 backups at a time, which can be an issue in some situations, so I would have to manually download backups from the server to my PC every time.

It would be nice if there was a feature in the config to automatically upload backups to a third party hosting site, for example, https://fileditch.com

so this would hypothetically create a txt file and save content like:

" : "
" : "
" : "

and so on, so I can just open the file and get the link to whatever backup I need.

in a similar way, it would be nice if there was also a feature to automatically send a copy of all backups to my local PC, so then when my PC's storage gets full I can deal with the backups later :)

I agree with this idea in spirit, but managing remote storage is notoriously tricky to implement reliably. Given that failure could be disastrous I'd strongly recommend leaving this to dedicated tools like rclone and not complicate the mod any further than "write file to disk".
Maintaining one storage provider implementation might be doable, but soon requests will come in for supporting Google Drive, OneDrive, Dropbox, (S)FTP, S3, NFS, SMB and every other obscure system you can think of 😅

For reference, SimpleBackups recently rejected a similar feature request: ChaoticTrials/SimpleBackups#25.
It's worth noting that the last comment is easily misinterpreted without the context of the linked discord thread, that discussion was almost exclusively about adding an option to run scripts before and after a backup.

Maintaining one storage provider implementation might be doable, but soon requests will come in for supporting Google Drive, OneDrive, Dropbox, (S)FTP, S3, NFS, SMB and every other obscure system you can think of 🥲

Fwiw, smb and (s)ftp can be mounted as if they were drives on most systems, and should work as normal. (tested with smb, not sftp)

Fwiw, smb and (s)ftp can be mounted as if they were drives on most systems, and should work as normal. (tested with smb, not sftp)

Transfer protocols would definitely be easier to implement than specific cloud services. WebDAV would also be nice if feasible.

I might've discussed this with Heather before on Discord, but an SPI-based system with built-in implementations for "write to disk" and perhaps the most ubiquitous transfer protocols could be a nice balance between functionality, maintainability and extensibility for daredevils with special needs.