I wrote an RTS tutorial series for Godot. Each post discusses a particular mechanic in detail. I discussed RTS camera system, units (of different kinds), selection system, path finding using both Godot’s built-in navigation system & my own custom navigation system, RTS resource management and so on.
Tutorial Link: How to Make an RTS Game in Godot
These are some images from the tutorial series:
I have tons of other tutorials as well on my website, on different games. You can see all posts.