Then I'm out, I want something that can fit in a pocket.
Did you really think a handheld more powerful than a Series S or the Xbox Ally X would fit into the size of a PS VITA? Not even Nintendo could do that with their ARM64 chip and Switch Lite.
Only thing that fits into your pocket is a phone, with Remote Play. Maybe check out the AyaNeo gaming phone.
For most cases, every game with a Xbox Series S version should run on it. Developers will support the current Xbox consoles for, at least, 2 years into next generation.
More like 7 years at least, cross gen is never going away.
I would certainly hope so. But like you pointed out, it's the delta between the handheld and the TV box that is the concern.
I think if there's one company that can force dev support, it's Sony, due to their global brand leverage. But even that has limits.
I think each major company can mandate two SKUs for devs at most. A third SKU will piss off so many devs and make them either reconsider or do bad rushed work.
So from the looks of it, MS will NOT be mandating handheld support. They are simply using scalable Xbox PC SKUs with three tags, Playable on Handheld, Mostly Compatible, and Handheld Optimized. They won't be using fixed spec hardware for handheld either, just scalable hardware that iterates and improves every year or 18 months.
So MS will either have mandatory support for a S tier SKU, basically Magnus X and Magnus S, but not mandatory support for Handhelds. Or they may just do one single Magnus SKU but have devs do three presets, 1080, 1440, 4k. That way they could refresh hardware every AMD gen that fits into those three presets.
But Sony will be doing the two SKU fixed spec strategy so definitely mandated support.
Free cloud saves that can transfer from my PS5 to my handheld PS6. This is what I love about Steam. I can play on a PC and shutdown only to instantly pick up where I left off on my Steam Deck.
Only Xbox and Steam/Epic offer free Cloud Saves. Don't think Sony will get rid of the paywall over cloud saves. Gets even more interesting if MS gets rid of online paywall with Magnus. So Sony would be charging for both online multiplayer and Cloud saves.