Thing is, what files should be removed on the remote client looks more like a remote client decision from where I’m looking. The typical “sync my pictures from my phone to the server, let me remove pictures on my phone” flow, which is similar, is something like
- Set up the source and destination devices as usual
- Set the “ignore deletes” option on the destination
New files from the source get synced to the destination. Files deleted on the source remain on the destination.
In your case you may want to set the “ignore deletes” option on the other side, and have a periodic script to remove old files on the destination, or something like that.