Thank you all for your comments and suggestions. I have Windows 11 25H2 on a Dell 3680 Precision Workstation (tower), which is the subject of my original post. After being at wits end without a viable solution, I focused on services (tried everything else first).
Long, long story short...Dell installed two (2) "services" that were each individually causing the problem. With these two services disbled, everything "works fine". Of course I don't have the "value" of the services.
The two Dell services are: 1) Dell TechHub & 2) Dell Trusted Device.
If you are having this taskbar issue and running a Dell, you might try disabling these two services. Your milage may vary, but you can always put them back to "enabled".