Success with loading old version of Numbers
If this helps anyone out, great. I was unable to find a workable suggestion online, and the Apple Store employee who tried to help me was only able to suggest that I buy a new laptop. I just had success with a workaround though...
I was given a hand-me-down MacBook Air 6,2 running OS X. I wiped it, and updated to Big Sur. The laptop is so old, that it is not possible to update beyond Big Sur 11.7.10. When I tried to load Numbers, I got an error message saying that OS 14 or greater is required, and there was no option to load an older version of Numbers. (For a little backstory...I have never owned a MacBook. I have an iPad, but I use PC's for my laptops. I do have Numbers on my iPad...but when I am on the MacBook and I login to my App Store account, Numbers does not show up as a previous purchase, so there is no option to download a previous version).
I logged out of my App Store account, but remained logged into the MacBook. I had my sister log into her App Store account on my MacBook (she did have an older laptop with Numbers installed). At that point, the App Store did show that there is a previous version of Numbers to be downloaded/installed on the MacBook...which we did. She then logged out of her App Store account, and I logged back in. Numbers now is installed and running on my MacBook.
Good luck everybody. Hopefully this will help someone else get past this ridiculous hurdle.
MacBook Air 13″, macOS 11.7