I need help with Collider Meshes

So I made a Car Model in blender and I made a interior and I want to be able to make it so my Character model can go inside the car. I have found this very hard to do because I’m not good with collision, I can’t use mesh collider because it doesn’t work without convex and I can’t have a convex collision mesh, I don’t know what I can do so can someone please help me.

You may disable the collisions between your character and the car colliders when the character is about to enter inside the car, then re-enable them after exiting. Use Physics.IgnoreCollision for that.