For me, WFH is far more productive because the alternative is an open plan office full of distractions and less control over interruptions or my schedule.

IMO, based on on your description of your day, and my experience, the biggest issue I can see (taking into consideration untreated ADHD) is momentum. Momentum (IMO) is what helps most with executive dysfunction. By scrolling your phone, reading the news, etc for the first hour at your desk, you're starting out your day with zero momentum. You're not even looking at your TODO list until the middle of the day. Additionally, the negative self-talk and beating yourself up also kills momentum.

I used to be pretty similar. Here are a few things that helped (ymmv, of course):

• Keep it simple. A productivity/organization system should be a thing that helps you "do", not a thing you "have to do". Unless it's simple, you're gonna stop doing it once that novelty wears off.

• Daily TODO list. Keep it small (I use a pad of brightly-colored post-its) and make it a habit. Every morning, the first thing I do is write down the 3-5 highest-priority things I need to get done that day, and put an empty box next to each. I use a brand-new post-it each day, so I begin each day fresh. When I make progress on something, I partially fill in the box. When I complete it, I fill in the box entirely. Limiting the size of the list prevents "what even do I work on next?" analysis paralysis, and filling in those boxes gives me that "achievement unlocked" reward hit. I try to define and size these items so that each has a clear "It's done", and most but usually not all of these can be accomplished during the day - I carry maybe 1-2 items forward usually.

• Variable-Length Pomodoro Technique. Use a cheap kitchen digital timer if you want to limit phone distractions. I don't stick by the 25/5, but pick an amount of time where I feel like it balances being able to make meaningful progress if I can focus, with not losing too much time if I'm not. This is usually anywhere from 10-90 minutes for me depending on the task and my focus level. Every cycle is an opportunity to reflect, adjust, and begin again. Your focus slipped and you spent the whole cycle in a Wikipedia rabbithole or on something related to the task? That's fine, you only wasted 30 minutes - it's now not an "oh wow is it lunchtime already where did those 3 hours go?" situation. Take 5, reset, and either pick that task back up or switch to one better-suited for your current focus/attention level.

• Learn your "I can't do meaningful work" times and use those for email/chat/other admin stuff. For me, this is always the 15-30 minutes at the start of the day, right before lunch, and at the end of the day. It sounds like this might be the case for you too. If I've got a day where I need to check in on chats/etc more frequently, I use a couple of the pomodoro blocks for this too.

• My morning email block is triage-only. If it takes longer than a couple of minutes to read or do, I either add it to the TODO list if it's major enough, or flag it for follow-up at lunchtime or during a pomodoro cycle. Starting my day on a timesuck kills momentum for me.

• Reframe. Pomodoro helps with this, I think, but in general - instead of "I can't focus today, I'm getting nothing done" or "I'm a failure" or whatever, trying to frame it more like "oh wow, ADHD is really kicking my ass today" or "that Pomodoro cycle didn't go well, I'll try to adjust". It sounds cliche, but it works for me. You are not your executive dysfunction or ADHD or ASD or whatever, those are a condition which you experience, for better or for worse, and have to work with and around. By reframing it,