@mfigueredo96, grab the fbx exporter off the unity package manager (free), one of the bars should allow you to export as fbx and i believe binary is the one for allowing blender tweaks, this should fix the prefab issue

the sdk is in it

Won't work for me, I don't think this has a prefab... it also makes its own prefab when I try to upload, can someone help me with this?

i need help with it i try and upload it but it just makes a prefab idk why

I expected this to attach itself to the already existing page for this model so sorry for the lack of information.
Also I was misinformed about it being physbones and didn't check for myself before uploading, and had no way to cancel the upload. Sorry about that, but I've already sent in a message to the staff for deletion.

its not even physbone

DynamicBone (not included)
PoiyomiToon (included)
DynamicPenetrationSystem (not included)
VRCSDK3 (included)