>>306152197
Booth models in general can be incredibly unoptimised, regardless of price. You'll want to delete or merge all meshes you don't plan to use to minimise draw calls and tris. 

Dynamic bones are arguably the worst for performance so check those and make sure you're optimised - Aim to have no more than 32 transforms. To get it that low you might want to merge bones in Blender, add exceptions to the dynbones, or just outright delete some dynbone scripts.