Even if a game is 80/20 in physical sales (let's assume 75/25 w/ digital) for PS vs Xbox a publisher may still see it as good enough. Porting to Xbox from PS or PC from what I understand is extremely easy and cost effective. PS has very similar hardware and Microsoft has Direct X for easy console and PC porting. So the cost of porting is very low, so let's say Tales of Arise needs 20k sales on Xbox to cover the porting costs, and it sells 100k. That would be totally worth it for Bandai Namco.
I think this is the reason we're seeing a lot of big Japanese games now coming to Xbox when during the Xbox One era some games skipped it. Game development costs are going up so adding more platforms will help with making that money back. As I stated above, porting to Xbox is just very cost effective. I think that is the reason some games aren't going to Switch. Porting costs for Switch are a lot higher for these bigger budget games, so they need to sell more to make that money back, especially since it's been proven Switch owners mainly go for physical games which gives publishers less money than digital. So for these publishers it just makes more sense to have an Xbox version over a Switch version.