While there is cross-pollination between macOS and iOS Macs are general purpose computers. And while it is true you cannot, like most PCs, crack open and customize a Mac and that to date most games are developed for PCs and not Macs as a side-effect of this (game development and hardware/graphics card development are incestuous), Macs are extremely capable computers that can meet demanding needs.
I have used Macs and PCs all my life. At this very moment I am playing Assassin’s Creed Odyssey in full pretty mode on a PC while my Mac in the other room renders a film and I type this message in an iPhone. I prefer using my Mac over the PC for most things - and certainly the Mac is where my bread is buttered - my PC is a fancy launcher for Steam.
Without being impolite, it sounds like you looked at the Mac, but didn’t bother to actually use it for anything practical, tasks at which it excels.