I focused heavily in blueprints for about 1 year before I got lucky enough to score a position at my first company, but I had a decent background in devops and security from college.
I’d say focus on Algorithms and Math(Physics). If you want to focus onUE4, I’d build prototypes every month and do self-imposed game jams as well as larger official game jams. Get something out on steam and look a bit into networking in UE4.
I’d also say to try to make content that you can reuse for multiple projects. Thats fast and easy to use. Gameplay Programmers might be asked to build tools to help speed up development over multiple projects so knowing how to build great tools will help you be a great programmer.