As you said yourself, it’s not the same thing. Proton can occasionally beat Windows because Vulkan might be more efficient doing certain things compared to DirectX (same with other APIs getting translated to other API calls). This is all way more abstract compared to CPU instruction sets.
If Qualcomm actually managed to somehow accurately (!) run x86 code faster on their ARM hardware compared to native x86 CPUs on the same process node and around the same release date, it would mean they are insanely far ahead (or, depending on how you look at it, Intel/AMD insanely far behind).
And as I said, any efficiency gains in idle won’t matter for gaming scenarios, as neither the CPU nor the GPU idle at any point during gameplay.
With all that being said: I think Qualcomm did a great job and ARM on laptops (outside of Apple) might finally be here to stay. But they won’t replace x86 laptops anytime soon, and it’ll take even longer to make a dent in the PC gaming market because DIY suddenly becomes very relevant. So I don’t think (“PC”) gaming handhelds should move to ARM anytime soon.