Hi. I forgot to mention my godot version. Here it is:
Godot Engine 3.2.3 stable
In the "Rendering" tab in settings, under "Batching", I have "Use Batching" and "Use Batching in Editor" enabled. However, as you can see, the draw call is still enormously high (same as the one in the picture), which is kind of weird. So I'm not sure why it is so high.
I tried applying one shared material across all the panels, yet it didnt change anything.