GDscipt and visual script is extremely similar in functionality and structure. If there is something you can't do with visual script, then chances are you couldn't do it with GDscript either.
As for a Trading Card game, Godot is a good engine for one, it matches with the engine style
Open world, games is something Godot isn't too good at yet, it is missing a lot of basics like a LOD manager. But if you keep it simple you could get something working.
Making a computer Card game is no different from making one in the real world. Only instead of physical objects you will be using Digital.
Just Google "How to make a TCG" and follow the same steps.
You probably also want to work on the card game with some paper cut outs to prototype the basics.