Today I tried something new.
Previously, I was changing default minecraft item custom model data for Executable Items. I did it by using a video they showed and it was working really well

But after that, I tried changing the custom model data 0 instead of 1, 2 etc to change the default skin of an item
The problem is that, since that change, nothing from that is working anymore, I don't even have the custom skins on the other custom model data …