I have a similar work behavior and I structured my work time in a way that helps me keep focused and not get off track: I usually work on a single project for 2

I have a similar work behavior and I structured my work time in a way that helps me keep focused and not get off track: I usually work on a single project for 2 or 3-day periods, rotating between ALL of my current projects depending on what I feel could use my time the most. I generally try to keep projects interesting by incorporating new things I've recently learned into either the project itself or the tools I'm using. The trick I've found is to never let anything get boring, by constantly rethinking and improving things that have gone stale, instead of starting new projects whenever you get another train of thought.