AH! I now see that Big Sur has jumped to OS XI — I didn't catch that previously, largely as I plan to hold off any upgrades for a while as most everything seems to be working well in 10.15.7.
Thanks again for your instructions. I decided to edit my feedback slightly. Here's what I submitted as a "bug" rather than a "feature request", seeing how this most helpful feature is now mysteriously missing... ;-)
I have discovered a bug in the recent OS offerings from Apple — Overscan in Displays is MISSING!
No telling what kind of gremlin got into Apple's networks, but it's obviously a very evil one sent directly from Microsoft in attempts to remove features that have set OS X far above the silly & useless offerings of Windows.
How many times have I witnessed Windows users wrestle with their stunted display options, omitting part of their presentations on their screens, while I suggested, "Simply adjust your Overscan slider... you know, like in Displays on my Mac!"
"What? Microsoft didn't provide an Overscan slider??? What kind of clowns are operating that silly outfit?!? Don't they know what we computer users NEED by now?!?"
PLEASE find & destroy that MS Gremlin ASAP!!!
8-)