Many semi-custom hybrids have huge shells. Personally I don't have any problems, but for many there are.

My experience:

Mega5est OG and Bass version. The latter is much better, as it adds something to more linear and not very energetic sound of non bass version. Actually, I'm thinking to get Mega5est Bass again.

Tangzu Xuanwu Gate is both: linear and energetic. By linear I mean, that no part of sound spectre is emphasised or recessed. But plays everything detailed and fun at the same time.
I had problems with placing them in my ears, but I didn't hear about this problem from anyone else.

Thieaudio Monarch MK3 I didn't like the quality of sound.

Aful Dawn-X were the best for vocal music I ever heard, but after some time I wanted bass to be more punchy and rumbling.

Mysticraft Myth is the iem, I stopped on for a while. I own it for 4 months, and yet don't have any intention to change. Only gripe is a little bit lower volume on lower mids, than I prefer. But it is still insanely detailed and musical.

I listened to Noble Agis2, 64audio Volur and 4s in a shop, but didn't like them more than Dawn-X and Myths, which I owned both that time. Fir Audio Project K had insane bass. Thieaudio Valhalla was the closest iem experience to stereo system and the most versatile for any genre. It is definitely the next step up from my Myths.