Yes. Both parties have to share the device on which they want to run warpinator out to the tailnet of the other person. If you already use tailscale for other personal stuff I’d recommend you make an additional tailscale account, you can use to connect to other peoples tailnets, as on linux you can simply switch between them with ‘tailscale switch <id>’

On any Fedora based distro you can quite easily install the proprietary nvidia drivers (this is necessary for a good experience btw). For windows programs you could take a look at winboat, it basically spins up windows in docker and it doesnt need any configuration whatsoever. For an animated wallpaper, KDE Plasma has a wallpaper engine plugin. Its a bit fiddly as I remember and not every wallpaper works, but its good enough for me.

I use Warpinator in combination with tailscale

Chants of Sennaar, Rain World, Celeste