Godot 4: 3D scene in 2D environment from the scratch (SubViewport tutorial)

Hi everyone! This is the third part of the video, where I explained the possibility of using 3D objects as part of a 2D scene in the Godot Engine. It turned out that the previous part was not entirely ideal because I explained the individual parts of the solution using the finished code of our game, which utilizes our own structure of classes and functions. This time, I am returning to this topic for the last time and will create the puzzle from scratch, as an entirely new project in Godot 4.