I don't think what you're asking for is possible to do with the product. If you unselect the files/folders, then nothing will be checked for retention, since only selected files and folders will be checked against the repository of what's in backup storage. I'll check with this team to see if there are any settings that can get close to what you need by avoiding backing up additional files.

What I'd probably recommend you do is just disable the backup schedule, and then manually remove the backups once you no longer need them.

I'll reply back if I get some additional guidance from the engineering team.

Whenever we replace a server, and choose to re-upload all the data, we put a note on the calendar for 90 days out to remove the old server backup data., We use Cloudberry Explorer to do the deletions.
If you are not replacing the machine, but simply want to stop doing backups, keeping the same server/PC, then simply identify and delete the folders that you no longer need (after your retention period expires). You can do this kind of deletion from the server console (once you turn on the Organization: Companies:Agent Option that allow deletions from the console.

OK thanks, yeah I can manage it manually if necessary