Best headphone/iem to be used with Sound Blaster AE-9

Request you guys to share your opinion for best Headphone/IEM to be used with Sound Blaster AE-9 on a PC for gaming. This means, I'd prefer to utilise the SB AE-9 to the fullest and skip the wireless ones which come with their own DAC.

I reckon that open backs are better for Competitive FPS and closed backs for Atmospheric/Single player Adventure games, but since I play both, I would like recommendations in both categories.

Budget - Preferred USD 350 (each). If really out of the world, then perhaps USD 500 max.