It's not a book, but I think the most high quality introduction to Godot is by HeartBeast on youtube. I went through his "Pixel Platformer" video "Godot action RPG" playlist. These were quick and got me everything I needed to get started.
Here are some games I made as a hobbyist with godot, in increasing complexity:
- https://escherize.com/works/magnet - https://escherize.com/evermeet - https://escherize.com/works/vampire