So going back to the start of the conversation, neither GPU is completely shenanigans free. Both require research, documentation, and additional work. Linux has a learning curve.

Does AMD 'work out of the box'? Sort of, but it really depends on the card and distribution. I know with Arch for example, things like scrolling in Youtube were horrendously laggy and I spent a few hours trying to install missing packages trying to figure out what was wrong. I haven't tried any other distros with an AMD card, but I've run PopOS, Ubuntu, and Arch on Nvidia without significant issues (other than modifying the kernel cmdline), but let's be honest that's less work than setting up almost anything else you're going to run on Linux.

Booting off a USB is also incredibly easy, and it's probably something everyone should have some experience with. Less than 3 hours after a fresh install I accidentally removed my user from the wheel group and lost sudo privileges ...