For those curious Swen spoke a little about the issues with Xbox they've been having and why they haven't officially announced the game for Xbox yet in this interview on SkillUp a few days ago.
Basically, the gist is that it's just not ready yet. They are currently trying to optimize it well enough so it runs 60fps even with 4 player co-op split screen which is a tall ask for the series S. Rather than hold PC and PS5 back they are instead focusing on their release and then will continue to work on Xbox after much like they did with Switch for DOS2.
Although this is frustrating for XSX owners like myself, it is absolutely the right thing to do. I've played a little bit of early access on Stadia and I hope all the PC and PS5 players are having a blast.