INTJ

Unfortunately, I don't think I have ADHD so I won't be able to answer that portion of the question, but I can answer them as an INTJ. Prepare for a wall of text ahead.

--Relaxing for me involves getting deeply into something. Be that a TV show, video game, YouTube rabbit hole, or even a neat Excel Spreadsheet. As long as I can reach that "flow" state, I feel very relaxed.

--I used to be a huge insomniac as a kid. I took me hours to fall asleep. Nowadays, I don't have very much trouble. I think having a pretty strict nighttime routine helps with this. By having a "plan" already in place, I can unwind a little while I mindlessly go through my routine and my body just seems to know when to go to sleep. This helped me a lot back when I was in college.

--Motivation is a place where I'm lacking. I am excellent at coming up with grand ideas and plans, but I'm awful with the initial execution. I found when it's something I particularly don't like (chores for example), I can actually get started by never slowing down to begin with. So for example, I know if I come home from work and sit down, I will not have the motivation to do much of anything. I have already shifted my mind from "work mode" to "chill mode" and that's hard to reverse. The easiest way to get those annoying chores done is to do them before I have a chance to shift into that "chill mode". If I have errands to run on a Saturday, I do it as soon as I'm up and dressed, and I do that as soon as I'm awake. If I take any time to relax with breakfast or a book, there is no convincing me to go out. because of this, I've accidentally become a bit of a morning person.

I think getting to know your own weaknesses like this can help you "hack" your own brain. I try to trick myself into doing things I really don't want to on a regular basis.

--This one I don't think I can answer fully. Just as you describe, I get very obsessed with things. I have approximately 1000 hobbies at this point and I'm sure I'll find a new one tomorrow. I've just come to accept that part of my psyche. I embrace it fully and enjoy the time I spend feeling excited about a new topic.

As for the focus portion of your question, I don't think I fully relate. Like I mentioned above, I can get into a flow state and really put all my energy into one thing sometimes, but usually, I'm multitasking in my mind. Right now, I'm listening to a YouTube video, typing this message, brainstorming about a Jeopardy category, and I know exactly where in the house my partner is right now by the sounds of his footsteps. It's creepy, but it's my norm. So my brain is typically running at high capacity 25 hours a day, as you put it, but it's usually because I'm focused on so many different things at once. And hey, I kind of like it like that!

--I am extremely fortunate to not have an addictive personality. I know it's a blessing and I thank my genes for it often. That being said, I do get "addicted" to things for extended periods of time. For example, I've been getting the same espresso drink just about every day for probably over a year now. It can't be good for me, but I do find it hard to resist. But knowing me, in a few months I'll hit "the wall" with it, and feel a little bored. At that point, I'll need to shake things up a bit.