Versatile programming language

Hi

I work with java at work.. In last year i've worked on (react/redux, graphql, vuejs, react native, angular, elixir/phoenix ...). I want discover new things

i want now work on an technology for "mastered it". I haven't lot of time so i prefer work on only work on 1 technology at server side (i will keep react/react native for front-end)

In your opinion, what is the most "versatile" programming language for back-end, for example :

• Web server
• Deal easily with databases
• Doing intensive CPU task (resizing image ...)
• Doing data analysis, IA ?
• ...

I would do lot a different things with my future programming language.

Any suggestion ? (I was thinking to python, but i really don't know anything about it)

Thank's