Yes, unfortunately, you are correct. The original [June 25] version of the KB503902 update caused certain computers to restart over and over. Microsoft said that this mostly affected configurations using virtualization features. The update was re-released [on June 28] to computers whose telemetry indicated that they were not using virtualization features. However, this introduced new problems that cause the Taskbar not to display correctly in certain circumstances.
Going back to your problem, Microsoft said "Affected systems may ... require recovery operations to restore normal use." That's something nobody wants to hear. A post in PC World has instructions how to deal with this. I have copied the instructions below:
"If you’ve installed the update on your computer and it enters the never-ending reboot loop, you’ll have to wait until Windows 11 begins the Windows 11 recovery environment by itself.
When it does, select Troubleshoot, then Advanced Options, then Uninstall Updates, and finally click on Uninstall latest quality update. Then confirm removal of the update.
It will take some time for KB5039302 to be removed. Once it’s done, restart your computer and it should work properly again."
Please try that. If that doesn't work, your next step is a reset. Best wishes for your success.