I wanted to remote desktop from a Debian machine to another Debian machine. Both have Xorg installed, i.e. the target is not a headless server.

Installed xrdp on the target (server) side:
sudo apt install xrdp

Installed xfreerdp on the client side:
sudo apt install freerdp2-x11

Run xfreerdp to connect to xrdp (my target hostname is “basement”):
xfreerdp /v:basement +glyph-cache /f

The “+glyph-cache” is a workaround for https://github.com/neutrinolabs/xrdp/issues/1266. The “/f” is for fullscreen.

Further reading: https://linuxize.com/post/how-to-install-xrdp-on-debian-10/