You talk about "self-motivated" folks. How important is the "self-" part to you? I recently watched an interview with the Mathematician Terence Tao (https://en.wikipedia.org/wiki/Terence_Tao) who is known (among a lot of other things) for being very productive while working on different areas of mathematics. From his answers it is getting clear, that he is very much influenced and motivated by other people. The thing that drives him, is when someone comes to him with a difficult question and he is able to help.
Maybe try to connect and collaborate with other people from early on. The sense of being useful is known to be a good motivator.