Alternative to mesh collider with convex checked

I have a mesh that has holes, which I would use to enter and exit the mesh (it could be anything: a car, a bus, an RV).

The first person controller cannot get inside a mesh collider when the convex checkmark is selected; although for physics purposes, you need to have a convex collider if you want collision, so I am looking at ways to solve the issue.

If I create multiple box colliders for example, covering only part of the mesh (like the exterior), would that be a solution or there is a better way to do so?

There is no other alternative that i’m aware of, and using multiple primitive colliders on objects is more efficient in terms of computational time complexity than working with a mesh collider.