Somewhere there's the intersection of: (a) what you want to do - i.e. your interests & 'passions', (b) your skillset, or potential to learn a skillset (c)

Somewhere there's the intersection of: (a) what you want to do - i.e. your interests & 'passions', (b) your skillset, or potential to learn a skillset (c) worthwhile problem to work on (d) something that will financially support you; but this is not a concern in your case (e) something that provides you with dignity, purpose and meaning in life I like the idea that it's an optimisation problem, to seek something which achieves these criteria and maximises beneficial impact to society.