In Mint Linux 19.3, when you install xrdp, the dependencies are not automatically added. If you are having trouble with display (blank screen), you need to install the xorgxrdp, xorg-video-abi-23 and xserver-xorg-core packages as well.

# apt install xrdp xorgxrdp xorg-video-abi-23 xserver-xorg-core

I will update the post after trying in the latest version.