I'm not sure if I have ADHD, they say if you get a high from the medication you probably don't have it. But I always play music. All the time. It has to be music I already know for focus. If not working, podcast. Or some YT video. I also am a loner/have lived alone for a few years so idk it's a way to not remember that I guess.
Can chime in on your first comment: back in 2014, I tried cocaine for the first and only time in my life, while at a fancy bar. While the rest of the people went pink faced and got "high" from it for the rest of the night, I got extremely sober and calm from it (and it burnt my nose). I didn't know at the time I had ADHD or even what the disorder was all about. Diagnosed last year at age 32: so much of the last 20 years of my life makes sense now, all the little coping mechanisms, impulsive behaviours, my relationship with caffeine and so on. It's like seeing yourself for the first time.
I cannot imagine what any of the ADHD meds feel like for normal people, and I suspect a good chunk people don't have the same experience from caffeine. For some, it probably makes them sharper & more awake and so on, but for others it would calm them down and centre the brain and make you feel "normal" for a bit.
In college days when you use it (not prescribed) at least for me I felt amazing. Like everything I did was correct example playing a guitar every chord was played right. I could sit down and cram for 12 hours straight (pretty amazing) and take an exam. I was better at conversing with people since I could focus on their face/not look away/be in the moment.
But yeah that euphoria part is not great. Because you can do the wrong things too/be focused on that.