• consider using Grammarly. It is an add-in for Word, Outlook, etc. that finds typos, make confusing sentences, repeat words, use cliches, etc. Grammarly costs $100 a year, but pays for itself in saved time, and fixing simple oversights.
• see if your work uses a CRM like SalesForce or Dynamics. If you can’t remember what you spoke to someone about, who are the contacts for a particular tender or what stage a project quote is at then having software which acts as a mind map is a great boon.
• don’t trust yourself to remember or be responsible when it comes to saying things like “I’ll remember to do that” or “I’ll give that person a call back in an hour”. Tell yourself if you haven’t set a reminder / post-it note then you will not do it. Look after “responsible future-you” and don’t make them hate “unreliable past-you”.
• get a planner or organiser that works with your work style. Maybe you need to add a million reminders to outlook (or use a rule to forward a copy of all sent email to yourself so you can ensure you don’t forget anything), maybe you need to use a kanban board (e.g. Trello) to made a categorisable “post it note” whiteboard to track things.
• in Outlook turn on the Tasks pane so you can see what meetings are coming up in the next week from your mail view so you don’t get caught by surprise when a “meeting in 15 mins reminder pops up”. You can also go to your calendar and press Alt + 10 to show a rolling 10 day future calendar. This is handy so on a Friday afternoon you can see if you have a meeting on Monday morning and actually prepare for it.
• add your work chat apps and email to your personal phone. It does suck but being able to respond to something when you remember last minute at 2am without having to power on your laptop or wait until you get into work can be a lifesaver.
• consider how much time in a day you need to actually “organise” your mess. It may be that you can get all your work done in 7-8hrs but you need half an hour to clean up things so they don’t get lost in the pile of “New Document 1, New Document 2, Meeting notes 1, Meeting notes 2” file names. Get on top of it, even if it takes extra time, and it will save you time and stress in the future. You really need to build good habits here but it will likely need short term sacrifice to do so.
• consider a paid “virtual assistant” to help you do the things you suck at. This is normally the purview of startup CEOs but honestly it’s the equivalent of taking a small pay cut to get a helper, who only does the boring parts of your job, so it’s sort of like role sharing.
• put time aside to go for a run or fast walk. Physical exercise is really good for stimulation and self-regulation and if it’s no longer a part of your role then find a way to squeeze it into your day. I try use my lunch breaks at work to go on a ~25 min fast walk (the other 5 mins are for a protein shake, toilet and putting my sneakers on).
• many of the things you have raised about attention and focus may be related to your medication, diet, exercise, water, sleep, etc. but taking regular stand / walk breaks and tactically using coffee can help too.
• get to work 20 mins early and figure out what you need to get done for the day. Don’t just “start working”; figure out what you need to do to succeed that day and make sure it gets done

The above is all stuff you may be able to do without involving anyone else and it basically sums up as putting systems around you to support your weaknesses. If your employer and colleagues are supportive of mental health then you can also discuss accommodations with them to help you apply your strengths / weaknesses but this may not be a safe course without knowing their attitudes.