Use another well maintained tool such as VRCFury
A Unity plugin that automates adding and removing accessories on a VRChat avatar.
It can do the following:
- import a 3D model and add it to your avatar
- merge the armatures (if the bones align)
- suffix all bones to help you find them
- remove an existing accessory (including all bones)
- prune (delete) any "loose" bones (that have no parent mesh)
- prune individual loose bones
- add way to add missing bones so armatures align