N64 wouldn’t have been considered “constrained” when it was new though. To be honest it’s not really constrained even now, not compared to the sort of hardware you were discussing earlier. And it’s rather disingenuous how you keep rocking back and forth between current generation consoles and 20+ year old tech as if it’s all current hardware. It makes it rather hard to reply to your points when you then when the goal posts constantly get shifted.
PS5 would easily run Linux considering the PS3 had a few Linux distros ported to it (back when Sony endorsed running Linux on their hardware via the “Other OS” option, which they later removed). Linux is pretty lightweight by modern hardware standards anyways. It’s just not suitable for every domain (but what OS is?)
On then topic of consoles running Linux, pretty sure I have a CD-R somewhere with Linux for the Dreamcast. That was the era when consoles really started to converge on a modern-looking software development approach.