I don't know how they managed to do it, it's pretty much magic.

Unfortunately my experience with IEMs is limited to the two that I have and both are outside your budget so I can't give you any good suggestions.

But if you follow this sub you'll see there is a new IEM coming out basically every other week that is somehow the most budget friendly and also best IEM. So I think you have a lot of options to choose from, probably even more than headphones.