As far as I know, yes, xRDP is still supported on Ubuntu 23.10.  Multiple blogs shows how to configure and use the software against UBuntu 23.10
in XRDP, Black screen usually happens because the same user is already logged on locally while trying to login locally.  You might get more information in checking the logs  /var/log/xrdp.log and /var/log/xrdp-sesman.log.
Which Desktop interface are you using ? Gnome or other ?
You can always try to use the script we have made that ease xrdp installation but no guarantee it will work for you.....
You will first need to run the script with -r option (to remove your xrdp install)
and then you can simply run the script with no parameters
Full instructions on how to use and link to the script can be found at xRDP – Easy install xRDP on Ubuntu 20.04,22.04,23.XX (Script Version 1.4.8)
Hope this help
Till next time
See ya