Why not docker Duplicacy? Can you expand what you mean about it not supporting local storage?
In the docker container you should map the internal path to the share so it can "see" the share to back it up.
I've got Borg + Vorta running and it's a pretty nice setup. I was able to set up Borg with a simple config file, and it's been rock solid since. I'm not much of a CLI user myself, but this one is user friendly. You can get a free Borgmatic repo 20GB to practice uploading as well. This would be my first recommendation just because of how powerful the deduplication is.
Duplicaci is my secondary that I'm playing with, backing up to a cloud. The GUI was semi-intuitive but I had to do some research on how to use it.
rsync is easy CLI that you can set up with a userscript, but, I'm not sure about versioning. This seems like a straight copy.
Duplicati can burn in a dumpster fire.