in general not having much bass is suggested for gaming advantage to hear footsteps easier. at the same time it also makes audio sound bland and uninteresting. you cant have both fun audio and advantageous audio at the same time without making concessions.
for the record, its entirely possible to play and be good at a game without using equipment recomended by other gamers. while there are certainly advantageous or disadvantageous products skill trumps those. use what is comfortable for you and what you are happy with.
with that said, open are generally suggested as well for soundstage but some closed cans like the dt770 arent terrible in this regard and can certainly be used. most closed cans do not have good soundstage but the 770 is fair. not as good as open cans, but not as bad as most closed cans.
if you want a bassy headphone and prefer fun sound over any advantage, need closed isolating cans and something comfortable the dt770 works. the 880 is a more neutral open can while the 990 is an open v-shaped can. both are also good. i certainly recommend it if those are the needs of a user.
akg cans tend towards bright, mid/treb focused, hard to drive without good equipment or they sound like crap. with the right equipment they can certainly sound great but are picky. good if you realize the characteristics normally associated with them.
the ad500x/700x/900x are also worth looking at. if you can stand the headband design they are great bass light headphones for gaming. easy to drive.
different headphones respond differently to amplification. some do not benefit while others sometimes get just a bit more bassy or full bodied. the akg cans will never be bassy though no matter how much you spend on an amplifier. you cannot change the nature of the headphones in such ways.
amplifiers themselves can have a certain sound to them. some run a bit warm (push things towards the bass side) while others are neutral, while others like tube amps have a certain unique sound to them. this can certainly change how headphones will feel. again, you arent going to turn a bass light headphone into something with deep bass.