I figured it out after I posted the question to the forum. I restarted my Macbook (2020 model) in Recovery Mode (Cmd + R).
Once I was into the menu, I selected 'Reinstall Mac OS." As soon as I made certain that I had a good Wi-Fi connection on my home network, I let Apple load a new version of the Mac OS.
It took no more than 45 minutes from start to finish - with no stalling or freezing.
Afterwards, I checked "About This Mac." It reports Big Sur 11.1. Success!
Evidently, when you do an OS reinstall, you get the most current version, in this case the exact updated version I was trying to install in the first place.
Sometimes, even a blind squirrel finds a nut or two.
Thanks to all who contributed.