Did you read the linked thread?
Some folks, who have the issue described there, have had some success not reinstalling everything, so that when the issue does happen they aren’t dealing with repeated massive download times/data amounts.
I’m sure that Microsoft/Asobo are working on a solution here. They have to be. The Xbox is Microsoft’s hardware and Flight Simulator is their flagship software for it. It’s just going to take some patience on your part to either workaround the issue, as others are doing, or forego using the sim until a solution is found.
I know that is horrible and not what you want to hear, but it is reality.
Deleting and resurrecting your user account is probably not the solution nor would I expect it to solve your issue. If that is even something that can be done, its going to be a massive amount of effort on your part and, most likely, won’t solve your issue. The issue is with the sim and how it handles content downloaded via the Content Manager. That issue needs to be addressed by the developers.
I’m sorry you’re facing this. It is a totally messed up situation and not your fault.