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.