Avatar has way too many triangles in unity

I just wanted to make my own first avatar to try it and I somehow managed to make a model that had around 17 k triangles in blender have over 2 BILLION in unity without any changes except for adding materials, I have no idea where I messed up and after hours of searching unity forums and reddit posts I’m resorting to this because I have no clue what’s going on, I am very inexperienced.

Mesh read / write is likely disabled.