If you care about job security and salary, I recommend specializing in maintaining COBOL legacy codebases for the financial services sector.

There are not enough oldtimers alive to do it, and the younger guys refuse to learn it. That drove up the hourly salaries enormously.

I am non-ironically considering this as I probably have double-digit organizations within a radius of 10 miles that probably still have core systems in production written in COBOL.

What about your sanity