My problem is that I made a "cosmetic" and I'm unable to upload it. I have a file .unitypackage and the system froze in "updating" when I try to upload...

It's just a case of editing a file or two. The game does not check for invalid settings in some cases, so a mode like this will run just fine. I'd rather not say exactly how I did it, because some options can lead to game lag and people crashing out. If you've got something specific and stable in mind I'll happily make it for you though.

Hi, how have you uploaded it?