Hey Paul! Thanks for looking into this. I did have Window Blinds installed as well as Adobe Premiere Pro (video editing) and Photoshop (my photography) both video-taxing apps. I uninstalled WB, but still had no success.
I messaged a contact at MS about another issue and through a lot of troubleshooting and investigating--despite the fact I was not on an Insider Build (not for a long while), the "control-scroll-lock" trick gave me the GSOD and said "Your Insider preview has run into..."
Somehow, despite all evidence to the contrary in the OS/Registry/winver/on screen, etc, part of the OS still thinks it is an insider build and for some reason, going beyond build .819 triggered the taskbar issue. This was true on all the PCs. I got a glitch in the software somewhere which was "shared" to my other PCs thanks to that feature meant to save bandwidth and pull code from machines on my network.
There is no way to fix this. Save turning off the feature, shutting down the other machines and doing a totally isolated clean install--and that would have meant a day on the phone contacting the myriad of software programs to "reactivate" keys, tokens and so forth. Then installing them.
Whatever 'fragment' which flagged the OS as an insider build could not be cleared by an in-place upgrade, would always be 'shared' to the refreshed PC. It was not a virus, to be clear. I've never had one and can't afford to loose 80K photos even with backups to the cloud and an external HD. (the time involved would have me down for weeks) I have several terabytes of data. I have Norton and Acronis Cyber Protect Home Office guarding against any malware or ransomware.
This is truly bizarre and the ONLY way to clear it according to the consensus is to do the one thing that will guarantee transparency won't work at least for now. Join the Insider Program. When it finalizes to the public if "queued for disenrollment" is checked, the machine will be offramped and no more code fragments, it will be all sealed up and I'll get the BSOD and be on retail for sure.
So, I'll just have to wait for Start11 to catch up after the next version of Windows rolls out later. It won't be a full-fledged feature update--rather they have switched to "moments" where they release ready features into the wild when they are cleared, wrapping them all up with a final "moment". One this spring, summer and if the past is any indication the fall will be the final "moment". I don't know if they are going to call it "23H2" or what.
I do know some of these "moments" which are finalized beyond insiders may be released to production versions as optional packages in Windows Updates. Heads up for the programming and engineering teams. If all of the sudden tickets start flooding in or the forum burns up after an optional "moment" update is offered to the general public and things like the taskbar or gawd knows what no longer work right, that's probably because they've (had) released a "moment".
Thanks to everyone who spent time helping me every way you could. It wasn't a Start11 issue. It was a code fragment issue. It's an issue I'll just have to wait on.. and that's okay.