Gameguard has conflict issues with the audio program Nahimic 2. Exit Nahimic 2 from your task bar to prevent GameGuard from torpedoing PSO2 on startup.
Edit: Disabling similar audio programs if you don't have Nahimic 2 ( e.g. Alienware fx) has also helped others
I'm bumping this so others can see. Doing this seems to have helped a lot of people in the other places I've posted it
Holy Crap! I've been installing and uninstalling both PSO2, Tweaker, and other related Xbox apps, repeatedly. Playing with different settings, file permissions, scouring boards... since launch... and all I had to do was disable AlienwareFX AND Alienware Sound Center.
I tried just disabling AlienwareFX, but it wouldn't launch until I disabled Alienware Sound Center as well.
This was a beautiful find. Thank you so much!
I uninstalled Tweaker, deleted the game, reinstalled it through Microsoft Store, then disabled AlienwareFX and Alienware Sound Center, and the game launches through Microsoft Store with no issues.