I think it's interesting that you're experiencing delamination over and over. I'm wondering more about the installation and maintenance? I install a lot of tips and delamination is something I very seldom see, and if I do see it, it's often due to the customer installing the tip wrong, prying the layers apart or using way too much heat or burnishing the tip to death.
I sell and install a lot of Kamui tips (Certified dealer, I get my tips straight from Japan) and I don't see the issues you are describing at all.
I think all the recommendations you have gotten so far are good suggestions, but I would pay attention to the installation and maintenance. please don't use a tip pick. Use something like the Last4ever tip tool is my absolute favourite.