Earlier quoted context omitted.
I really hope you lock it down to something like Tailscale so that you have a private area network and your Samba share isn’t open to the entire world. Samba is a complicated piece of software built around protocols from the 90s. It’s designed around the old idea of physical network security where it’s isolated on a LAN and has a long long history of serious critical security vulnerabilities (eg here’s an RCE from th…
It seems like every network filesystem is irredeemably terrible. SMB and NFS the stuff of security nightmares, chatty performance issues, and awkward user id mapping. WebDAV is a joke. SSHFS is slow. You can get really crazy with CephFS or GlusterFS, and for all that complexity, you don't get much farther way from SMB/NFS issues with those either. My solution: Share nothing and use rsync.
I’d say Dropbox et all is closer to a good design but their backend is insanely crazy optimized to make it work and proprietary. There’s an added challenge that everything these days is behind a NAT so you usually end up needing to have a central rendezvous server where nodes can find each other.
Since you’re looking at rsync where you want something closer to Dropbox, I’d say look at syncthing. It’s designed in a way to make personal file sharing secure.