I'd highly recommend reading Atomic Habits. One of the key concepts in the book regarding changing habits is developing or changing how you identify yourself. From your post, it appears you like starting things. More details from authors blog here:
For me, I started diligently tracking what new interests I develop. Before I picked up a new topic of research or area of interest, I would put it in a note and evaluate if this would take me closer or further from my overall goal. I stopped spending too much time on a new interest if it did not align with my overall goal. "If you can't measure it, you can't improve it." It is really important to be self-aware of this trend, and you have shown that you want to improve.
https://jamesclear.com/identity-based-habits
For me, I started diligently tracking what new interests I develop. Before I picked up a new topic of research or area of interest, I would put it in a note and evaluate if this would take me closer or further from my overall goal. I stopped spending too much time on a new interest if it did not align with my overall goal. "If you can't measure it, you can't improve it." It is really important to be self-aware of this trend, and you have shown that you want to improve.
Good luck!