I havenāt used NFS myself (yet) but it migh be more reliable than KDE Connect; Iāve had issues where machines donāt āseeā the others properly from time to time, for example.
Speed-wise I donāt think there will be much in it. Only way to find out is by sending the same file(s) several times with each connection method.
afaik KDE Connect is a complete different use-case.
Itās for sharing, control, etc. with other devices like your phone.
Itās not for sharing storage devices of networksā¦
The OP just wants to copy files to the server, which is generally fine and Iāve found it pretty quick.
Itās also handy in my case to get the notification pop up on the target machine. No idea how an Ubuntu Plex Server handles that sort of thing though.
KDE Connect covers a lot more use cases, but still works over wi-fi networks.
The difference is that for devices to be able to communicate, KDE Connect requires to run on all, while NFS usually has built-in support without additional apps.
Speed in general will be bottlenecked by your router, AFAIK neither implements stream compression.
No. KDE Connect is another use case - and not very stable.
Using NFS is a native *nix communication protocol and it is as fast or slow as any other fileservice depending on the network and serverās hardware and the configuration.
Every filesharing method as proās and conās and requires different levels of knowledge when it comes to setting it up and securing the service.