Hi,
Since you have already tried standard driver updates and Group Policy overrides for WDDM and UDP, this specific failure is a flaw introduced in recent Windows 11 updates where the host fails to allocate virtual framebuffers for dense multi-display layouts. Since your system is actively blocking a rollback of the problematic update, the best permanent fix outside of your single-monitor connection workaround is to wait for an official hotfix from Microsoft.
In the meantime, you can try to bypass the layout negotiation crash by forcing the client to connect using a matching, static resolution file instead of relying on the dynamic full-screen multi-monitor handshake. You can do this by opening your Remote Desktop Connection client, navigating to the Display tab, unchecking "Use all my monitors for the remote session," setting the slider to a fixed custom resolution that spans your screens, and saving it as an .rdp file to see if that stabilizes the connection.