Help my sekhmet avatars chest bone dissapears in vrchat

[HazyHoneybuny]

so for the past few weeks i have been trying to upload a sekhmet avatar however even though the chest bone is correctly mapped in unity upon entering vrchat whether desktop or vr the chest bone just stops existing?? and my viewpoint which is supposed to be in between the eyes is right in her chest instead.. ive tried removing physbones from the breast bone to see if maybe that would fix it that did not i would fix it in blender however i cannot open the blender project and im unable to the blender file i cannot update blender to a newer version because i have a 13 year old dell laptop which lacks a dedicated gpu and thus it cant use newer versions of blender (my version of blender is 3.2) so i have attempted to export the fbx from unity (because the avatar model creator didnt put an fbx file in the purchase downloads) and was met with an unholy abomination of polygons.