I regularly delve into both communities and here's some interesting stuff I found:

1. Unlike mechanical keyboards, Headphones transducer and their pads account for more than 95% of the sound you'll be hearing. Difference from anything else in the chain (cables, DACs, amps, etc.) is miniscule and when present, will be nowhere as exciting as simply buying another pair of headphones. You'll also need a music source of decent quality, of course.
2. EQing your cans to a single FR target is comparable to putting foam into your keyboards. It might improve the sound, but you'll be making all your different headphones sounds very similar, if not exactly the same. When EQing, try to just tinker with what you feel the headphone is most lacking and leave the rest stock.
3. Keyboard mounting styles (gasket, top mount,) is comparable to transducers type (Dynamic, planar, electrostats). Different flavors for different people, and tuning one type to sounds like another is not easy.
4. Sennheiser HD6x lineup is the Cherry MX of the headphones, Old but gold. Whereas you'll only find vintage cherry mx users in the deep end, old mate senny is often recommended here. Also they last forever.
5. open-back headphones are perfect for listening to both your music and your keyboard. The classic argument "you won't hear them (the keyboard sounds) because you'll be using headphones anyway" doesn't apply with open backs.