Linking xbox games on steam. Let me know if possible and/or how!

You mean leader boards or downloads?

If downloads only games you purchased on steam or various stores work with their own client

He wants to PlayAnywhere games he’s bought on Xbox onto steam

No, not even. Microsoft games will do that. playAnywhere only works on the microsoft store and only on titles that support it

I don't believe you can as it is 2 distinctly separate platforms. An example of this Forza Horizon 4...when they released it on Steam earlier this year, you still needed to purchase it again even if you owned the MS Store copy.

you can log into steam via geforce now and stream all, well most of the steam games you own as nvidia runs all the games via there own hardware servers which consist of a mix of rtx cards, you cannot do this with gamepass as microsoft won't allow it due to having a competing platform as xcloud.

geforce now has much lower latency than xcloud which has been documented countless times.

They don't provide the games they just give you access to games that you own on steam and run a version that is on their servers. works very well.

Hello again, I don't know how the processes work on Steam, but if it's like the Xbox and other digital platforms, you'll need to know the email account you used to buy the game.

And even if you have access to the account that bought the game, I don't know if it's possible to transfer a game license from one account to another on Steam.

At Microsoft this is not possible.