So these are the problems my girlfriend is having:
The game seemed to have nuked itself.
The store wouldn't let reinstall.
She manually tried deleting what files she could remaining in the folders to uninstall but could not.
She installed PSO2 tweaker but at this point it's just saying something about documents and OneDrive which makes no sense to me.
We did this command in powershell Get-AppxPackage Microsoft.GamingServices | Remove-AppxPackage
Which finally allowed the game to install again but we used the microsoft store again and now when pressing the play button we get this error.