Thanks Very, Very Much for your time & efforts Ricardo Dias Marques !!
I did the steps you outlined & it is showing in the menu - but still does not open.
Just to be sure I also did this:
sudo apt-get install libgl1-mesa-glx
To which the system responded:
libgl1-mesa-glx is already the newest version (21.2.6-0ubuntu0.1~20.04.2)
Most likely I should have also mentioned that he also uses Zoom & Skype to reach family members flawlessly via the same USB webcam via his HDMI display.
This Webex app is just not a happy camper !!!