Collision generally works best with convex shapes.
Collision that’s as complex as your mesh with hundreds of triangles, will use a lot more CPU than typical convex decomposition hulls (or plain boxes.)
A spline will deform the mesh, so even if it looks convex in Blender, it might become non-convex and invalid when bent/deformed.
Recommendation: Define simple collisions. Use a simple box for that if possible.