Yeah so here are the steps I took. I made sure to try and restart/test as frequently as possible to make sure I knew what worked.
First tried normal trouble shooting mentioned above: uninstall and reinstall, try different Internet options, etc.
I then made sure to check for an update for any of the ally specific stuff as it seemed like maybe it was a reading error on their end. I did find out I was like two updates behind, tried in between both of those and it still wouldn't load.
After seeing wilkat mention arcraiders, I ran through their subreddit and found a lot of other people with ROGs with the same issue and tried a variety of things mentioned there.
First, I uninstalled the Xbox app. At first I believed that it would also uninstall the other apps used for Xbox but it did not. Reinstalling it did not trigger any updates or anything, but the game did not work.
Then, I uninstalled 'gaming services' ((settings>apps>"gaming services">uninstall)). Opened Xbox and loaded the game, no luck.
Went back to settings>apps> xbox, clicked the three dots for "advanced options" then scrolled and hit 'repair'. No luck there.
Someone mentioned the insider program on one of the subreddits as well. I joined also and it didn't work after for me. I ended up putting the system down for a while bc I was irritated and then someone mentioned that they weren't getting prompts for updates, so I went to the Microsoft store for search for updates and when I did is when the update popped up that finally made it work.
It is possible that some combination of things made it work for me - I just updated to the most recent version of the Xbox app and I can still access it. So whether that's a gaming preview update or a normal one, I'm not sure though.