With teams like MS and Apple also working on it, I expect this to be figured out on a faster timeline. Months/ few years.

That assumes they will share a meaningful amount of work. I do not see what Apple have done to help much at all - completely closed ecosystem with their own custom chips that they are not going to want to share.

MS have done a really bad job as well at getting ARM to kick off and have not been putting a huge effort into it that I have seen. And especially since valve is doing this in part to get away from MS systems why would MS help valve with this goal?

So yeah, if they did put in and share the effort it would take less time. But I don’t see them doing that. Plus, it takes years to develop a product like this. And all evidence ATM suggests they have barely if at all started on the next version. Which does suggest that the next deck is likely more than a year away, likely two. Which does increase the chances that it could be arm based.