Thanks for posting this!

My 2 cents is that as you get more used to ADHD symptoms, you can learn to ride the waves a little bit. The intensity of your interests can be powerful, and you'll find ways to partly channel it. A few tips:

• Practice being kind to yourself. Accept that you'll get derailed, and learn to get back into it.
• Get used to your patterns. It takes ~20 minutes to get into a task and ~2 minutes to lose focus (less for us, lol), so remember that there is always a 20-minute wall of effort every time you need to get going. That's the barrier you'll get better at pushing through as you practice.
• Build your environment to suit: get rid of clutter (if that bothers you), close doors or wear noise-cancelling headphones if you need quiet (I'll always love rainymood), you close other apps, leave your phone far away, and turn on self control.
• Consider multiple media. When I'm stuck it can help to switch from typing to writing, diagramming, or going for a walk and talking aloud, using speech-to-text on my phone.

Note: I'm a content writer rather than a fiction writer, but there are a lot of overlaps (research, ideation, drafting, revision...). I was diagnosed with ADHD in college ~12 years ago, was on meds for 8, and have been off them for the last 4, which is also roughly the period in which I've built a freelance career. My relationship to ADHD has changed dramatically over that time, per the above.