Part of the reason that nvidia GPU drivers are so large, and they've been so unwilling to open source them is a good amount of nvidia's secret sauce for gaming is in the software. They'll work with devs on optimisation before launch with might disproportionately benefit their hardware, sometimes the drivers will fix games for devs, e.g. swapping out shaders for visually equivalent but better performing ones, or the z-index issues cyberpunk had if you didn't update to the "game ready" drivers. e.g. look at the lows for Tomb Raider or anything for Red Dead 2: https://www.youtube.com/watch?v=KIwIeobQSnQ

It's why when Intel moved from the GMA to Intel HD (i.e. "can just about render a desktop" to "can play indie games"), it took years before games even reliably worked on Intel GPUs, never mind performed. Of course once they did it pretty much killed off the budget GPU market.

Even at the high end consumer market, it's why you often find AMD GPUs outperforming cost equivalent nVidia cards for compute use but then falling flat in games.

Apple has the advantage that the big game engines like Unity/Unreal etc. have been targeting their hardware for the mobile support for the last while, so they have arguably a bit of a head start relative to Intel's entry, but I have to imagine they have a catch up to do before they run high end PC games comparably. Probably will run the entire iOS catalogue in 120hz though.