Woah, M2s sounds awesome! After more testing, the sound is growing on me!
Should I have expected the top end to have been recessed? I've been mostly using it via BT with my smartphone, I'm not sure if there is any EQ enabled, but the top end is pretty clear to those ears, it has good amounts of energy and impact, and the low end is amazingly well layered and has great amounts of detail, I wasn't expecting M2s to be this good actually , especially given its small size!!
I am really impressed with M2s! It is small, inexpensive, works like a charm, and it also looks kinda cute! The sound is too awesome! (using HiFiMAN RE2000 right now)