I'm no expert but your use of "atonal" and "microtonal" interchangeably here seems way off the mark. "Atonal" usually refers to music composed without a fixed

I'm no expert but your use of "atonal" and "microtonal" interchangeably here seems way off the mark. "Atonal" usually refers to music composed without a fixed sense of key - and was originally used to describe music written using standard western 12TET. It's a property of the music's relationship to key signatures - not it's tuning system.