Audeze - LCD-i3

They use extremely-high-end custom IEMs because they can afford them. It doesn’t mean their IEMs are give them special abilities. I have tested over 30 different IEMs in gaming, mainly Tarkov, from value $15-$900, and most offer similar performance. As long as you go with neutral IEMs that focus on clarity, and stay away from brassy/muddy IEMs (ie KBEAR Rosefinch) or open-back IEMs (ie LCDi3), you will do fine.

Audeze isine and LCD-i are the main ones. I think goldplanar might have also done a large diaphragm truly open back planar IEM as well, but that's about it. Unfortunately they're all completely broken in terms of tuning, and need heavy EQ work to sound normal. If you're hoping for one that sounds good out of the box, it's not going to happen. Most of what people refer to as "open" or "semi open" are just pretty conventional front and rear ported IEMs. The only difference being that they tend to have the back porting on the outer face rather than the side or inner face.