I think they're very tip-sensitive. Best two tips I've found for my ears are Auvio wide-bores and Complys. No sibilance issues with either in my experience
I immediately moved to wide bore Tenmarks and added a EQ to downplay the highs. After a month or so, I started reducing my EQ. I guess harshness is very track and brain dependant. After a while, your brain equalizes
Comfort was the most terrible issue that I got used to after several weeks.
In between all of this, I was listening to the IT01s and soundstage is the only thing that kept me giving the KZ5 another chance. In the end, I'm glad I did.
Thanks for your words.
I tamed down the treble this evening putting cheap foam tips bought from aliexpress.
Treble went down hard and it's now a bit more pleasant, but i feel i miss now the detail i had.
So i'm gonna try some tip rolling tomorrow as i have like 20 different tips from many other headphones.
Atm i wanna try without EQing as my DAP is cheap and only has pre-set EQs.