Maybe an unpopular opinion given how I don't see a single soul talk about this, but the notion that Kaz actually did try to overcome his fear of touch before he met Inej and even then the catalyst was a girl he used to like is actually so important to me.
It doesn't even take away anything from Kanej since that failure, the humiliation and frustration of it, is part of why he is as unforgiving and violent as he is and how he eventually got nicknamed Dirtyhands, so it's a little surprising to me how this never seems to be brought up in character discussions- at least not from what I've been able to see (I had a full year of spoilers for the duology before I ever got to read the books).
Knowing that Imogen existed at some point for Kaz, that receiving and giving physical affection isn't something he just point blank gave up because it triggered his trauma- rather, he always saw it as a worthy reason for him to try to overcome that pain... knowing that what made him ultimately gave it up wasn't really the very same repulsed reaction he gets from skin to skin contact in the first place but what failing the attempt to best it costed him, what he understood that yearn for affection would entail for him, how hard it was for him to crawl back from the shame of it which he never really did because otherwise he wouldn't have been so deeply hesitant to try it again...
I think it really puts into perspective just how self aware Kaz is of both his own suffering and the way he treats others, and of how those two things correlate. It's such a relevant part of his character.