The Xbox and PS5 are x86 but they aren't PCs. They are gaming appliances purpose built to run their respective purpose built operating systems. Without hacks, they don't do anything but only run code that's allowed to run. A Steam Machine is a PC. Yes, it's intended to run games (like any other gaming PC) but you can run whatever code you want on it.

Everyone loves to say the Xbox and PS4/5 are just like an x86 PC except for the fact they are missing a huge aspect of what makes a PC a personal computer. If the vendor locks you out of doing personal computing, it's not really a PC, is it? Refering to x86 as a PC is such an outdated way of thinking. I can go buy an ARM-based laptop and do more with it than an x86 console. Even an iPhone offers a more PC like experience than an x86 console. The Hubble Space Telescope runs a 486, does that make it a PC as well?