I've just got approval to publish the app to the Flathub, so you might consider Dragit:

https://flathub.org/apps/details/com.sireliah.Dragit

It's relatively simple p2p app with host auto-discovery. Payload is encrypted and performance is pretty decent. Built using rust, libp2p and gtk.

Edit: works on Linux and Windows; repo is here: https://github.com/sireliah/dragit