I used to code for some time, not very long, but I think I can share my opinion with you. If you know C# or other unity supported coding language try that. It is really easy to learn. But if you want to have more control over game code, optimisation stuff etc, try UE. The interface is a little intimidating when you start, because of tons and tons of options avalaible, but C++ is coding language giving you more control over final product, and I think it is also faster. That is only my opinion though.