The most fun internships/jobs I've ever had were all unpaid, because I could come and go as I please, and literally work on whatever I wanted. The second you're getting paid, your personal interests are thrown out the window, and your job is now to take orders from your boss.
Of course there are exceptions. I'd imagine that being a tenured professor would be pretty sweet (though getting a job like that these days is extremely difficult and competitive), or if you're a doctor then helping save lives in Africa or something would probably be extremely fulfilling. Being a politician seems like it would feel meaningful, and they get paid solid six figure salaries.
But overall, the search for a meaningful job that also pays decently and doesn't require crazy hours is like searching for a unicorn, so for most people with the talent/luck/opportunity of working high paying jobs, achieving financial independence first before seeking meaningful work is probably the smartest move.