Congratulations on your new brain chemistry. Its such an amazing feeling, and i hope you'll find out a lot of new things about yourself. For me I feel like I got my sense of self back like I remember myself from 20 years ago. For far too long I feel like I've been on autopilot, trapped in a constant fight for my own attention that has been stolen from me. I've been medicated for a year now in my late 20's and I feel so happy.
But remember this, when it inevitably becomes the new norm and you have a difficult day. You still have ADHD. The meds will never remove that. But you now have better tools to fight back what is rightfully yours, namely your attention. Remember to take a break sometimes and just ride the ADHD for a day or two when the meds are not working as they should for whatever reason. It'll bounce back and you will find out you are so much stronger that you used to be over all.
Be kind to yourself.
Well that's peak ADHD for you right there. New thing=dopamin. No dopamine any more = abandoned projektets. My best advice is to pick something that you can keep itterating on infinitely and keep interesting. For instance i like making smoothies and its something you can vary for ever and never run out of recipes to try. Basically food is a good hobby because there's so much to learn from the entire world
For gaming something like Minecraft can be fun because infinitely projects, but maybe harder to stay motivated.
3d printing is also good because there's something new constantly.