I used to use x2goserver which was and still is awesome.

These days I prefer docker-based KASM Workspaces, or if you just want a nice GUI over your "bare-metal" VM or server then KasmVNC is great and easy to setup (not that KASM Workspaces is hard to setup)

https://hub.docker.com/r/linuxserver/kasm https://github.com/kasmtech/KasmVNC