My IEMs sound very sharp, loud and quite bad compared to my headphones

So I just got to use these new Kiwi Ears Cadenza and I feel like the sound is odd compared to my headphones. I don't know if it's normal for IEMs or not, but it feels weird. It sounds very sharp, quite flat, and loud. I can't change eartips because I'm already using the smallest ones, nothing above will fit.