A:AnswerIf you mean the Meta (Oculus) Quest 2, yes. It probably wont be that good of an experience as it is powerful for being a handheld computer, but might struggle with some VR games. It would probably be better to just play the games directly from the Quest.
A:AnswerYour Xbox game pass, steam, GOG, EA, Epic games etc… accounts with all your games will work. Basically it’s a windows 11 gaming PC in the form factor of a hand held.
A:AnswerYou're completely locked into using their proprietary xg mobile hardware. Haven't seen anywhere that someone has home-brewed a way to use other external GPU setups.
A:AnswerThe overall answer is no. As long as the SSD you install doesn't cause any damage to the Ally or other components in it, the warranty will still be valid. The warranty would not cover the SSD you install into it, and if the SSD causes any sort of damage to the Ally, that damage would not be covered as well.
As long as you buy a reputable SSD, you shouldn't have to worry about it causing any damage to the Ally. I have installed a Sabrent 2TB SSD in my Ally, and everything is working perfectly, and I don't see it causing any damage to the Ally in any way in the future.