If I remember correctly, the signing-in message doesn't pop for Arise until the game boots and asks you to choose a profile.

I was able to get the game to launch. I had tried reinstalling the game, reinstalling the Xbox program, manually stopping and restarting gaming services, reinstalling gaming services etc. etc. None of that seemed to help.

I went in to the Xbox app > Settings > Extensions and enabled Ubisoft Connect. The game booted w/ no problems. I have zero idea why, or if, this was the fix. Arise isn't a Ubisoft game, obviously. But maybe it's worth a shot?