I have only been diagnosed ADHD two weeks ago and soon to be diagnosed ASD (at 46 years old). I can tell you that looking back, I can see so many things I struggled with when my children were small. I wish I had my diagnosis then and I knew how to help myself.
I had four under 6 and really struggled with just leaving the house. I think this would have been a problem with even one child - just getting things together for both myself and the children was a real pain, arriving on time to anything was hard and life was stressful and overwhelming. They were feral when in the house, so leaving to the park was a necessity (they were also diagnosed ADHD/ASD a few months ago at 18, 17 and 12 years. All were high masking until secondary school). I thought it was absolutely normal that we ran everywhere, they jumped on everything and was absolutely crazy on swings and roundabouts. Only after doing this was I able to enjoy their company. I also had an innate need to leave the house, and would fall apart if this need wasn’t met in the day.
They also whinged a lot, which was difficult to deal with when already stressed. I think with mine it was more the autism - needed to know the reason for everything. Finding it hard when plans changed. I found it hard because deciding on every little thing was already difficult, and they were challenging many decisions.
If I was to do it again, I would (like someone suggested) keep a good routine, with set times for everything (I need time limits to get out and get things done) and keep busy so that they wouldn’t spend time going stir crazy (they needed movement and release of energy). I think I would have also been a little less critical of myself, and just accept that some days it was just so bloody hard (still is).
Oh, and the house is never tidy. Ever (but maybe that is just me).
Hope this helps.