TigerVNC actually works well, I started using it over WAN recently and it's very smooth. Traditionally VNC has sucked. But it's still not as good as RDP in some ways.

I use VNC all the time and don't mind it, but an alternative that I haven't tried but which looks very interesting is Xpra [0].

[0] https://xpra.org/

For fun you could try texttop: https://github.com/tombh/texttop

There is an RDP implementation called xrdp - it's not too bad