In godot, is there a way to automatically set a position of a camera such that a specific object stays at maximum size, pillar/letterboxing the rest?

Question

I am trying to make a 2.5D Tower Defense game in 3D using Godot. My problem is that when I fix the camera to keep the map at maximum size, and then use another aspect ratio, it doesn't resize and pillar/letterbox the rest. Is there any way to do that? (Also, the angle I am using for the camera is exactly 20° from facing straight down.)