macOS Catalina - F1/F2 brightness & F10/F11/F12 volume keyboard controls broken

I have a iMac, 27 inch, (late 2013) with a 3.4 GHz Quad-Core Intel Core i5 processor. It has 8GB 1600 MHz DDR3 memory. Graphics are NVDIA GoForce GTX 775M 2 GB.

I don't know when it happened because I wasn't paying attention to it, but I am guessing it happened after I upgraded to Catalina version 10.15.7, but my adjust brightness keyboard buttons are not working at all.

I only noticed because my wife was wondering if I could turn down the brightness one night last week and....I found I could not. Neither the F1 nor the F2 button works. Wow.

I have an Apple Magic Keyboard that is recharged via cable. I have had virtually no problems with this Mac since I bought it, but this one is puzzler. Such a simple thing too...but, annoying when you're used to being able to do it with a push of a button. I just realized my volume control buttons don't work either. Oddly, the F3, F5, F6 *do* work....puzzling.

Does anyone have a fix? I am somewhat technology-challenged, which is why I literally gave you all the specs I could find when I'm guessing you don't need to know the graphics card specs for a brightness level issue. I have seen some smarter people talk about patches on other boards and that's beyond my pay grade. Thank you for any help.