Firstly give me the skill equivalent to the best in the field. If the rules allow it all of these skills listed and if not any of these :-
1. Computer networking to the point of having the same knowledge as the best in the field. Why? I am curious about that stuff and being able to work as a network engineer if I don't get a good Dev job

2. Cyber security. Why? I enjoy it and being able to make sure my code is not easily exploitable is a cherry on top. Also having a backup job in case I don't get a good dev job

3. Being able to communicate with non dev people about developer or non developer stuff easily and being a really good leader.

4. Being a good developer in whatever language I use and instantly being able to learn new programming languages and frameworks or libraries with ultra in depth information.