Okay so I’ve not thought long and hard about this but I’ve tried to put it in an image; it might be a good balance of performance and accuracy or it might be trash!
EDIT: Note that in some circumstances, the center of mass might be a better of choice but it likely depends on a few things.
Also, if you detect that these are primitive collider shapes (sphere, box & capsule), you can easily create fast-path checks for those as they are much simpler. I’m more concerned about arbitrary mesh-based shapes here.