First of all, M1 is not in any way an AMD CPU. The M1 in all its various incarnations is a product of Apple's in-house designs and is an ARM processor with zero relation to any x86 CPU(which is what AMD and Intel both make).
Back in 2005, when Apple announced the transition, it was prompted mostly by IBM failing to deliver on the G5 CPU(never reached the promised 3ghz clock speed, was always a power hog and never could get power consumption down enough to make a mobile CPU). Intel's roadmap showed much better performance/watt than IBM could promise and what AMD had in store. By late 2007 or so, there was very little that a Core2Duo in a MacBook Pro couldn't run faster in emulation than a G5 Quad(2x2 core G5s, liquid cooled, and I've measured at over 150W at idle).
That was 17 years ago. Intel has stagnated and AMD has stepped up their game. Intel is now having issues with die shrink, something that AMD and the ARM makers have down.
OS X/macOS never has had low-level support for AMD x86-64 CPUs, which are different enough from Intel in terms of specific instructions they can work with and that are the "backbone" of the OS. There are a few specific AMD CPUs that I've known of people shoving OS X onto, but it's not an easy task and is only half functional.
AMD is doing well enough now that I suspect that had Apple chosen to stay with x86, they'd have been giving AMD CPUs a serious look.
To answer the core question of this post, though, at the price point discussed for the use cases discussed, I don't think there's an appreciable difference. I'd definitely give an M1 Macbook Air a close look, though.
