Can't play Xbox Game Pass PC games. "Not available on your account"

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I get this error when trying to start up MSFS2020, after being hit with 2 "would you like Microsoft store package dependency installer make changes to your device". No matter what I chose, yes, no, or x, I get the error above, saying it's not available on
my account, despite having it installed. I've made sure my payment went through for the Xbox 1$ pc pass and will give a list of the things I've tried below. Please, I've been on with Microsoft support for 13 hours over the weekend, not counting time spent
in line.

I've tried: (not in this order exactly, but generally)

Making sure every windows update is installed, and drivers are updated (including optional)

Uninstalling and reinstalling the MS store

Uninstalling and reinstalling the Xbox game app thingy

Uninstalling and reinstalling a C++ thing from 2015 that had known issues with MSFS2020

repair and reset MS Store

Uninstall and reinstall Xbox gaming services

Sign in and out and back into both the MS store and the Xbox app

Deleting login info and doing the above again

Making sure I have enough space (Over 20G free after full supposed 127G install, but I'm only installing 20G off the store, so I'm assuming the rest is downloaded in-game on launch like others)

Resetting windows while keeping personal files

Doing the above all again after windows reset.

*End list*

After all of this, the problem remains unchanged. I'd appreciate any help. I'm at the point where I'm reconsidering starting fresh, and deleting everything, reformatting my drives, and going from there (actual recommendation from Microsoft support btw, and
probably will work)

Thank you all,

Marmite.

:)