Asking for advice on career

I began to work as a developer in 1998. I used to write code for J2EE projects and provide services to those projects. Later, in 2011, in order to help my wife teach our children at home, I quitted my job and started to work as a freelancer. I had done all kings of small projects with Flutter, Android/iOS development, Node.js, PHP. I did both backend and frontend with React and Vue.js. Although I could make a living and enjoyed the flexibility, I did not enter deeper levels in all the areas.

Now I am 45 and work as a non-IT guy in a Non-Profit organization. I enjoy the current job now, but I'd like to have a part-time job to have more income and continue my IT career. Based on my experiences, which path should I go? Should I continue coding or switch to cybersecurity or cloud management?

1, programming. Rust seems interesting, and I'd like to learn it.

2, kubernetes/docker. I used docker before.

3, cybersecurity. What is App Sec?

Any advice will be appreciated!