Godot (from the editor) does not compile the exports. It uses export templates, which are pre-compiled executables that just load the game content. For example, on Windows it will be an exe file with the engine, while your game (all assets and scripts) are within the pck file. This means that all games, on the same version of Godot, will have the same executable, just different assets.
There is usually no need to compile the exports yourself, you just do this through the editor to export your game. However, you can make custom export templates, for example , if you need to combine some native library into the code (used to integrated ad networks, for example). See here.
https://docs.godotengine.org/en/stable/tutorials/export/android_custom_build.html
