I have been tearing my hair out and my face off for hours and found the simplest solution. Same issue with using a Win10 computer and connecting to a Win11 remotely. I tried a million things at least and then this simple fix........
On the remote Win 11 computer I signed out. Then instead of using the PIN I selected other signin options and used my Microsoft password. Then RDP from the Win10 computer connected.
Unfreakinbeliviable!!!!!!!!!!!!!!!