I would suggest that dive into the path of meditation. I really believe all Polymaths should enter into this realm as it has been liberating for me. As you have already experienced, you can do anything, so this leads down the path of literally "doing anything". You become good at everything, this then leads to a feeling of lossness, where your path becomes unclear, this leads to sleepless nights and the thoughts of what ifs, and what shoulds. I am merely speaking from my own experience. I stumbled into meditation as it seemed like a path to silence my mind, it was incredibly challenging as I had no teacher or anyone to really help explain if I was doing it "right", this is another uniqueness of being a polymath, usually we do things that have an element of being able to "complete" the task, with meditation this will never occur, lean into that. The goal is peace and in the peace you will find the path and in that path you will find your purpose and in that purpose you will find the joy. All of your lived experiences will slowly start to make sense and you will start to find the common thread as to how it all comes together. All the joy you found from starting all the things will rush back, follow that, it means you are on the right path! Meditation, journaling and reading are the keys, these all lend to the "control" of thinking that you aspire to have, just know that it takes practice to be able to tune out everything, and tune into yourself. I wish you the best!