I currently use the Focal Elegia ($900) for gaming, on a SoundBlaster G5 ($100) external sound card (I would use it on a schiit stack, but sadly my current cable is too short for the headphones to be comfortably plugged in to my AMP, so I have to use something closer to the seat). It is very good in my opinion.
A Magni/Modi is a great intro Schiit stack (the combo runs ~$550, assuming you go multibit).
My plan is eventually to see if I can't get my hands on a Hifiman Jade 2 system and see how I like that for some gaming, but at the moment I haven't had a chance. I expect they will be amazing at music, based off of the limited experience I had with them at the RMAF 2018 CanJam. The Jade 2 and the Elegia both made my "want to buy" list afterwards.