How to adjust the opacity of the mesh in a map

Hi, I’d like to adjust the opacity of the mesh of map by rendering to get the mesh more transparent than the map. However, I can just adjust the backface’s opacity and I have no idea adjusting the opacity of the mesh, any suggestions? Here is my original map and the map I want to get.

Use the opacity property ?

I have tried it, but I could only adjust the whole map’s opacity(including mesh).I have no ideas adjusting the opacity of mesh individually.

What are you calling a mesh exactly ?