I also have had this problem since around Feb/March 2024, I have tried most of the suggested fixes but nothing seems to fix the problem without a full reset which gives me around a week to ten days problem free before the “missing essential updates…” returns. What I can add here is that it occurs even with an empty Community Folder.
One of the official fixes is to go to the Content Manager and manually install updates but how can you do that when MSFS won’t start because of the problem? Am I missing something obvious?