app switcher & app force quit menu commands are not working from external KB

This issue is important because I use app switcher constantly while I work. I've never had a problem like this before, and when I do have issues, I usually find the answer here on this forum, or another similar forum.

Mid-2014 15" MBP 11,2

1. Command-tab does not call up the app switcher from external wired apple keyboard. At first it was working intermittently, then it stopped altogether, even after shutdown and restart.
2. Command-option-esc doesn't call up the force quit window.

For the past 2-3 hours I've searched "app switcher not working" "command tab not working" and every variation I could find. I've followed every suggestion I've found. I've read hundreds of comments and a couple dozen threads in various communities. Nothing has worked.

• Command keys work for other operations.

• I did everything suggested on this forum and others.

• I rebooted, I reset PRAM, SMC.

• I checked the actual key, cleaned under it.

• I installed a program (karabiner) that allowed me to remap the key to caps lock, but even that stopped working. (uninstalled that program as soon as I discovered this)

I just need command-tab to work on the external apple keyboard so I can quickly switch between apps.

Data from EtreCheck attached. I thought I only had one Antivirus App, but it says I'm running two.

First entry in launch agents refers to "saicloud" - that is a weird app that I have to run in order to control a plotter I have. Seems odd that I have to sign into a cloud to operate something that does nothing more than read vector data to cut shapes in vinyl. I think I removed it a year or two ago and was not able to run the plotter.

Anyway, please advise - I have no idea about this stuff. I'll do my best to follow instructions.