Navmesh Generation for Static Meshes with Complex Collision only

I used to build my level from ProceduralMeshComponents, however, for performance reasons I then switched to StaticMeshes that I generate directly in c++ code from the ProceduralMeshComponents (similar to [this][1]).

Now, these StaticMeshes do not have any simple collision attached to them and I fail to see where could it be done programmatically.

I would be totally fine if their complex collision would be used for navmesh generation. The ProceduralMeshComponent has the flag bUseComplexAsSimpleCollision, but the StaticMeshComponent does not have it. So my question is, what can I do so the navmesh would be affected by static meshes that only have complex collision, no simple collision.

What I tried until now is now to set the Default Shape Complexity in the Project Settings to “Use Complex Collision as Simple”. In the editor I can then verify, that the static meshes get a collision model:

However, as you can see in the screenshot this collision is still ignored by the navmesh. Here are the mesh collision settings:

here is the navmesh recast settings: