Thank you. Almost everything is done with Blueprints. It is definitivly possible to make complex games without ever touching C++ code. I have a small C++ function in there that takes care of the correct rotation of ships by applying torque on a rigid body. That function involes a little bit of math which can become complicated in blueprint. Although I think the custom Math node that was not available when I started would make life easier today.
The downside of blueprints is that if something goes wrong, you are a bit lost. I am not sure if there is a way to restore corrupted blueprints but I don’t think there is. So make sure to commit changes to a version control system frequently.