I have both the headphones you mentioned. The Hifimans are significantly better than the at m50x. However, you have to have decent quality audio files, source, interconnects, amplifier and solid support to allow the Hifimans to shine. Once you give them a good signal I’m sure you will hear a clear difference. Contrary to popular opinion you don’t need extra special hearing, you just need to pay attention to the quality of the entire reproduction chain.