I've got this problem except with learning / studying.

I realized I am a lot into science and engineering late in life. Now I want to do all of the Khan Academy in Chemistry and Physics; learn nano-/bio-tech; learn cybersecurity... and probably should just stick to learning backend dev in order to get a job.

People call this being a polymath, but I am seriously concerned for myself. The best I can do is take it one subject at a time.

On the building side, I simply have no ideas I am interested going for.