Follow your obsessions until a problem starts to emerge, a big meaty challenging problem that impacts as many people as possible, that you feel hellbent to solve or die trying. It might take years to find that problem, because you have to explore different bodies of knowledge, collect the dots, and then connect and complete them.
Two things to note about being great people.
They are obsessed about their obsessions
It might take years for the problem in that obsession to arrive.