Open back headphones are good as well the ad500x won't have the m50xs bass but in the mids and the treble it is much more detailed and soundstage is just exceptional
I have misread it sorry however you can still find much better options for less like the m40x that sound Bradley identical for 50$ less or the shure srh440(+840 pads if you can)
And for more again the 770 just destroies the m50x.
This is really becoming a trend the m50x is not a good gaming headphone it got no soundstage you can get a much better headphone for gaming for less or for slightly more if the op can expand his budget the beyerdynamic dt770 will be phenomenal
If you can find them in your price point sennheiser ampirior are phenomenal yes thier in ear but they are reall comfortable and are on par with 300$ over ears sound wise.
Shure srh440+ 840 pads is another good option
Those are excellent options do note the dt770 isn't really portable I don't quite remember the specs but it might be a little hard to drive also looks and cable might be a slight turn off but aside from that a great choice.