I think the issue is that developers have to do something to add touch controls. I'm not sure, but it'd make sense as to why a first party studio gets touch controls added faster (like if they're told cloud experiences are important). Adding custom touch controls probably isn't too difficult, but I d explain the inconsistency if it's up to the individual devs.
What I genuinely don't understand is why universal touch controls aren't a thing on XCloud when they are a thing for Xbox remote play. Just create a default layout and make it available for every game. Gamers can decide whether or not to use it (and Xbox could even give some more options to customize it like we already have for games with touch controls). Then devs would just make customized touch controls on top of that if they want to, but XCloud wouldn't be completely reliant on them doing so. The touch controls for Minecraft Dungeons where you just touch the screen and Genshin where it copies the mobile app experience perfectly stand out to me. But it's not a like a universal default layout would hurt anyone. And again they already have it for Xbox Remote Play.
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