Dual Monitor Mode - checkbox appears but does not stay selected

I host a meeting that has been successful in dual monitor mode twice a day for 4 years.

Recently, due to a suggestion, I turned off "screen sharing" in the Zoom online controls both for my Meeting Account and also my Admin Account - to stop members from sharing their screens during a meetings.  

This somehow turned off my dual monitor mode.  It grayed out the option for Dual Screen mode. 

So now I've turn on Screen Sharing on both he Admin account and the meeting account, and this enabled dual screen mode so I can now select it in the Windows 11 Zoom client.

Now - I can go on the Zoom Client, then Settings, then General, I select Dual Monitor Mode and it checks.  I can move to Audio Settings and back - and it stays checked.  If I close Settings, and reopen settings, it is not checked.  And, of course, my friendly head mode does not appear on the 2nd monitor as it had done for so many years.

My PC is an i5 and fast and 16gb ram.  Windows 11 shows two monitors side-by-side, and I can even move the (one) zoom window from one screen to the other screen.  I have rebooted the PC. 

So my problem is trying to make the checkbox stay checked.  Does anyone have ideas?