mesh collider - performance

Hello,

I want to build a VR locomotion system where you can teleport yourself around.

I have a huge environment, which can't be approximated with primitive colliders. So if I use colliders I need mesh colliders.

My question is now how big the impact on the performance is, if all my meshes are using mesh colliders, but I only have a single raycast.

And how big of a performance impact is it if all my meshes have mesh colliders but there is nothing which interacts with the colliders (raycast turned off)?

Huge environment means ~2M tris.

I am happy about every opinion on that topic!