@Zskot, I don't have GTA. The only thing I have in my Epic Games launcher is the Unreal Engine, but I think any game should work the same.
I found this command to run the Unreal Engine by creating a shortcut, then right-clicking the shortcut and clicking properties. This was in the "Target" field.
"D:\Program Files\Epic Games\UE_4.25\Engine\Binaries\Win64\UE4Editor.exe"43ff44a8-6474-4990-9a8d-c5287e68425c-image.png
2d94f44f-d1e3-4fdf-8ace-c59778e56c72-image.png