Non-Convex Mesh Collider triangle limit - is it more than 255?

Question is as per title.

I am create a system that generates large structures, but it also generates lots of triangles. I want to be able to create a mesh collider for these so that the terrain itself can have physical presence among the moving objects in my game.

I generate a large number of triangles in the process, and I am going to put aside some time to see if I can optimize these meshes into fewer triangles or otherwise make them more lightweight performance- and memory-wise.

However, reading the docs for Mesh Colliders ( https://docs.unity3d.com/Manual/class-MeshCollider.html ), I noticed it said only convex meshes have a triangle limit of 255. I am certain that the broken-down chunks of my structures will likely have more than 255 triangles.

I plan to have these objects as completely static for the most part so no rigidbody seems necessary, and so it doesn't seem like I need to set it as convex. Does this mean that without a rigidbody, I can have more than 255 triangles in the mesh collider provided it's not convex?

A side question that's probably also important: should I expect inaccurate collision detection if there is no rigidbody attached to the mesh collider due to the skin-thin nature?