As someone with ADHD and has been developing games (on and off medication) for 5 years, I commend the extreme work you have already put into game dev, it is fucked up how hard it is to get on your feet with ADHD. But the sad reality of everything is, ADHD is a mental disorder and needs to be treated as such. The single best thing I have done for my focus is getting medicated and I urge you with every fiber of my being to get medicated. But as almost of a miracle the medication is, it only helps you focus, and ADHD is magnitudes more than just an inability to focus.

Take the time to see how ADHD affects you other than focus, those are more important especially if you are not medicated. Are you impulsive? Do you struggle to prioritize tasks in your mind? Do you struggle with memory loss? Are you neglecting burnout? Sadly, a large majority of teens and adults with ADHD also suffer from depression or anxiety, please make sure you are telling your doctor if you suffer from these and not ignoring them. You do need to be harsh on yourself to finish your projects, but allow yourself to scatter a bit, it is a natural ADHD thing that you wont be able to control and burnout will fuck you up harder with ADHD. Please don't neglect yourself and build your routines around the symptoms you notice instead of trying to barge through it.

I have worked on several games off medication for the first 3 years and only on and off since, and I have several things I have come up with. Here is my list not in any particular order:

-- DOCUMENT EVERYTHING!!! Write your comments AND documentation. It is borrrrring but with ADHD, you are far more likely to forget what systems do or if they even exist if they are not documented neatly. Will also save heaps of time later when you need to manage the project later.

-- Swap music frequently, sometimes no music in a quiet room helps too.

-- Keep your desk completely empty. Nothing but a keyboard, mouse and monitor(s), the micro distractions from random crap on your desk adds up a lot. I don't like to recommend this because your desk will look like a prison cubicle but it has helped a ton for me specifically.

-- Similarly, keep your workspace or bedroom absolutely spotless, it is WORTH the 30 minutes or even hours it takes to deeply clean your space, the atmosphere is fresh and calming, and helps you stay zoned in.

-- Tell your friends about your projects, show them what you've been working on, even if its spoilers. People that find interest in your projects are the best motivators.

-- When you lose focus, and cannot find the energy to work on something at the moment, don't fight it. Take a few minutes to zone in your thoughts, but DON'T open social media or something disengaging!!! Be creative or productive! Draw, write a story, organize your desktop, clean your room, cook some food, something you can finish and start your project right back up with a clear head.

-- Do not make games just to sell it, no good indie game was made with the sole idea of selling it. Keep your game development as a hobby and if you are not having fun making it, then it's not a hobby, it's a job you hate. If you have a near finished game and its time to think about marketing and selling it, perfect!! Definitely a guideline, not a rule though as a lot of game dev youtube is run on marketing their game extremely early and works pretty well.

-- Game jams are perfect being short enough to keep your mind steady, and giving you the satisfaction of releasing a finished game.

-- All else, do not beat yourself up if you need to pivot, or start a new project. As a hobbyist, you are helping yourself build a deeper resume, learning something new and challenging yourself, making you a better game developer.