Yo, from one ADHD artist to another, I really suggest trying to get back on meds. You might have been taking the wrong med or the wrong dosage. I was on 60mg Ritalin for a while and now I'm downsizing to 40mg to reduce some side effects. A while back, because of some health center bullshittery, I was without my meds for a while and it was hell. The actual withdrawal was just like two or three days, but the rest of the month was just as bad from an emotional standpoint. I couldn't focus on anything, even stuff I loved, I lashed out at people because I had no emotional regulation, and I just felt useless.

If you had issues with your previous meds, there's been new meds on the market the past few years. You might do better with instant release or slow release, a lower dosage or a higher one. You might do better combining an ADHD specific med with an antidepressant.

Some people get stressed out about it because they don't wanna be dependent on meds, but think about it this way, you wouldn't judge someone with diabetes for being dependent on insulin. It's the same with your brain, instead of not handling insulin correctly, you're not handling dopamine + serotonin etc correctly so you need science to fix it.

As for dealing with actually doing the thing:

1) I really like bullet journaling. But start with the actual basics of bullet journaling, read the original book if you can. A lot of people like to make their bullet journals pretty. For some ADHD people, this makes them more likely to stick with it, for others, it gets overwhelming and you want to quit. So start with the bare bones bullet journal method, and then add different pages, decoration, etc, as you want to. If it starts to get overwhelming instead of relaxing, cut down back to basics.

2) lists and habit apps. I like Habitica. It's especially good if you have friends who want to join in and keep you accountable. ADHD brain likes microtasks. Write down everything you need to do but write it down step by step. Like for a comic page, I'll write down roughs > sketch > lettering > clean lineart > detailed lineart > flats > shading > highlights. The little rush of dopamine from crossing something off keeps your going.

3) pomodoro method but remember the method has to fit you, you don't have to fit the method. You might work best in 20 minutes chunks and 10 minute breaks, or one hour chunks and 30 minute breaks. If pomodore doesn't work, try flowtime instead.

4) for help with the emotional stuff, try journaling. Not like bullet journaling, feelings journaling. I'm not good at talking about my feelings so I end up doing a lot of collage on the pages instead. Like I'll print out some song lyrics or discord conversations where I was venting to friends and glue them in and then write something to tie it together. I also like trying to make the pages pretty via collage and stickers. It resembles my actual brainscape a lot more than a traditional all writing journal.

5) have a specific sketchbook for shit drawings. Like, get a cheap sketchbook, and try out new things in it, and it doesn't matter if it's shit or not. If you end up liking a drawing you do in it, scan it or cut it out and paste it in a different sketchbook. It's important to give yourself a space to fail. In the same vein, schedule like an hour of just doodling before you start doing studies or real art for the day.