No surprises here. Just like the lockdown on iPhone screen and part replacements, Macbooks suffer from the same Apple’s anti-repair and anti-consumer bullshit. Battery glued, ssd soldered in and can’t even swap parts with other official parts. 6000$ laptop and you don’t even own it.
That’s a stupid and loaded question.
Define “faster”. In terms of CPU performance? Yeah, an M2 macbook probably still absolutely destroys 99% of gaming PCs. In terms of system RAM performance, again yes, M2 annihilates the gaming PC with a separate CPU and RAM.
dGPUs have their own integrated memory, that’s part of the reason why they’re so good. Have a look at game performance in current PC games when the game needs more VRAM than your GPU has - performance absolutely tanks no matter how much system RAM you have.