The exception is the notifier updater, haven't figured that one out yet. This alone tells me there is a relationship and something Windows 11 is up to, which I wish I knew what, but that relationship is removed if the third-party AV service is stopped. The issue above only seems to appear with Windows 11, even a fresh Windows 11 install, just Windows 11 in my experience. Clear you're on a bit of a rant, must have pushed a button and not my intention.
MSIX come from? I am not drawing the connection yet. In my case it's Cisco AMP that is the AV hence ignoring 'Windows Security' comment as this is not relevant in this case as it's a third-party issue.