FIX RDC for Mac 11.6.2 Big Sur

I am not the only one, but just another voice complaining about the insanity of trying to use the Mac RDC client (10.7.5) to connect to a local Windows 10 PC on my LAN from my Mac running OS 11.6.2.  It has become unbearable and virtually unworkable.  The RDC client window either flickers black, or the RDC client simply just loses the connection to the Windows PC, goes black, and then attempts to reestablish the connection.  The good news?  The connection generally reestablishes itself.  The bad news?  This can take from 15-60 seconds, rendering the PC unusable during the down time, and sometimes the connection only holds for 5-10 seconds before doing it all over again.  And again.  At other times, I can stay connected for 10-15 minutes at a time.  There is no rhyme nor reason to this, and I'm at my wits' end.  I've turned off hardware acceleration and also disabled "use system proxy configuration" as suggested in other forums, but no change.