After Unreal and Unity it seems the Godot engine is the third best known. There is a lot of hype about it, since it is completely free: https://www.youtube.com/watch?v=IPCv6F-IgXU.
To create a game you call and place various types of objects like KinematicBody, RigidBody, StaticBody etc in the Scene and then you create and associate scripts and attributes in the Inspector. I suppose you would want to call an object of type "Coin" from the Scene Menu, with the parameters of "Coin" set in the Inspector. Parent would be "Chi", new coin name "Crystals", number created 10 000, texture would be "Blue Silver" etc. There would be a script (in GDSCript, similar to Python) written about when and how the coin would be captured by the player and added to his/her wallet.
But the module "Coin" would have to be written in C++ and added to Godot (which is written in C++). That module, I think, would then interact with libxayagame, as you have suggested. Here is a video about creating custom modules in C++ in the "modules" folder of the Godot source: https://www.youtube.com/watch?v=LFtNGsjM8Js