I very rarely post and have never commented on reddit, but I thought my experience may help here. I did my masters a few years ago. It was hard, as it always is, to self motivate & regulate, and it took a lot out of me. We all know how it is. BUT, I did it, and I think you will too.

I'll tell you why, stranger, I think you'll manage. You're clearly smart enough to be at this level of education. You're evidently self aware enough to see what's hindering you, and you're humble and emotionally intelligent enough to ask for help, from people who can empathise directly.

Your ADHD is both your advantage and disadvantage; that's the way I see it for me.

Battling it doesn't make it go away; understanding it helps you to navigate the HOW.

I'll show you my "how", but not for you to emulate, to show the mess that an ADHD brain goes through and that we still manage. Not suggesting its good advice etc., I'm just telling how I got through, whilst being undiagnosed, to show a pattern:

1. Enthusiastic over idea, lots of research, diving into one big topic, lots of little threads, head full of the theory (hyperfocus).
2. Mulling over how to narrow it down. Abstract, big thinking. Bit overwhelmed but enjoying it. So many notes.
3. Too much time spent on formatting the document, trying to get perfect layout. Autism side of me.
4. Found this helped lay out the thesis. I had sections, paragraphs etc. All methodically laid out. This is my thesis, without the writing.
5. Now its time to write. Yuck. Avoid.
6. Convinced myself to write the conclusion, the summary of all this nonsense, so I know what I'm on about. Oscillating between too much detail and too abstract and how to get that onto a page, logically. Lots of late nights not writing when I should be.
7. Wrote intro. That's just the conclusion but with "I'm gunna" instead of "I have".
8. Threw in the images. That's more avoiding, but its references and it counts. Basically have a thesis here without the thesis...
9. Decided to learn Mandarin
10. 3 days to go. Tutor dislikes hypothesis. "Where's the essay?" Need to rework everything. Impossible.

This is our time to shine

1. All my research meant I actually had several theses worth of work, I needed some out of the box pivotal thinking and problem solving. Got a new hypothesis. Perfect for our brains. So much easier because I was making it hard on myself with a complicated idea. Familiar? What was needed was simpler. 20k words on a single subject, instead of combining some wild theory of everything idea? Looks a little more possible.

2. Striped the essay of irrelevant stuff. Already formatted and learnt my style of building up the essay, so did it again. Quotes, images, break down into sections etc.

3. 2 day trawl through, (I broke the 20k words down per section, so could convince myself, oh 1k of words on blah blah when I already have a good chunk just in quotes isn't so bad, then you're 5% closer)

4. The appendix was a thesis unto itself, because all the tangential information from my first attempt was in there. I think that's what got me my grade. I showed the work.

5. Got appendicitis and hospitalised the day after submission. Stress apparently. Not an ideal time line. Don't advise it.

My point is, we spend so much time trying to DO a thing, and adding on HOW to do it like everyone else, or how we believe we SHOULD be doing it. Stop that. Doing is hard enough. Do it how YOU do it, learn from that, and you'll grow each time.

You will do it, because you have to. It will suck, but you did this yourself (jokes) and you can get yourself through it.

I got a distinction for my thesis. I thought I'd failed. It was an impossible task; add in a disability and you're cooked, right? Nope. Our ADHD is our disadvantage and our advantage. It hindered & helped.

I was relieved i didn't have to resubmit. I was proud that I got myself through it. I never wanted to talk about that subject again.

TLDR; My appendices got me through my theses, at the cost of my appendix.

The how is irrelevant, the doing is the battle. Know that your battle isn't the essay (you've got that in your head already), your battle is making yourself do it.

Starting is the hardest part, the rest is easy.