Pi-4 Remote connection yields blank screen and "unable to acquire session bus"

Using Windows-10's "Remote Desktop Connection" utility I am unable to get to a working desktop on my Pi-4B (8GB) running version 20.04.1 (64-bit). Instead I get a blank (black) screen with a "Unable to acquire session bus" pop-up error that appears after a few seconds. This happens when I try to log on with both my normal user id and as root too. I tried going through the steps shown here (https://www.hiroom2.com/2018/05/07/ubuntu-1804-xrdp-mate-en/) to fix this, but they had no effect on the problem at all.

I have this remote desktop connection working perfectly on my other Pi-4 (4GB) but was inexplicably unable to get a cloned SD card of that system to work on the new Pi-4 (8GB) because a vertical quarter of the logical desktop screen was consistently shifted so the edge of the 1600x900 screen was appearing in the center of the physical display. I upgraded the firmware on the new Pi system to see if it would change the GPU timings, but that didn't fix this issue. This even happened if I tried to reinstall Ubuntu MATE from the iso that I'd installed the 4GB Pi with too - so I eventually had to install a base Ubuntu image from the Pi Imager (which did not have this skewed screen problem) and then manually add MATE and a bunch of other stuff to it - to get a system similar to what my 4GB Pi system got from its iso out of the box.

Any thoughts or suggestions would be much appreciated!

I found a successful workaround after reading that the ability to connect a remote display protocol (RDP) session with the same userid that was already logged in and using MATE had been REMOVED sometime around Ubuntu 18.01 - I set up a second userid and logged in as that. It worked and brought up a full MATE desktop.

Seems like there should have been a specific error message rather than just dumping the RDP user at a blank screen when the capability to logon multiple times with the same userid was removed. Not sure why I was able to logon both directly and through RDP when I ran Ubuntu MATE 20.04 on my 4GB Pi-4 (and it wouldn't work on the 8GB Pi-4), but at least now I can get a full MATE desktop through RDP which is a big step forward.

Not sure why I wasn't able to get a MATE desktop to come up through RDP when I had earlier tried to login directly as "root" either?