My 7yo has ADHD and I have had a bit of a realisation recently - I think fairly often he does something (e.g. overreacts to his brother/asks for something in an entitled way/makes a rude comment) which makes me (mentally) go "FFS!!" and I might respond in a bit of an irritable way, which then causes him to blow up and then - well you know how it goes trying to address that kind of behaviour in the moment, I'm sure.
The thing is, me being irritable or saying "DS. Come on/Watch it/Hey." this doesn't actually explain to him what it is that I am objecting to or what I am expecting him to do. I'm reacting as though he ought to know better and should be able to extrapolate from my tone that I'm irritated, meaning his behaviour isn't OK, probably because a NT child his age would know better. But the fact is, he either doesn't know better, or he doesn't know how to do better - it's not like he's pushing his luck in a moment, as all children do, because this kind of thing happens ALL the time. It's really predictable, if I sit down and think about it. What I should probably do is correct the tone in a more neutral way by modelling what I want him to say instead. There's no sense me being annoyed with him, despite the behaviour being genuinely annoying, because my annoyance isn't going to help him learn what to do, if that makes sense?
I made an analogy in another thread earlier about behaviour being related to skills (which I think it is close to 100% of the time) and I said if the skill was something like speaking French, you wouldn't expect "getting annoyed" or having a boundary to magically give them the ability to speak fluent French. You'd expect in the short term to need a translator, use simpler or shorter phrases, use pictures/sign language, and so on. This is like the accommodations and scaffolding we do for our ND children. And the English speaker can also of course learn French, but it will be slow progress over time and they will probably need a lot of those accommodations for a while.
The thing is that if you move to France and work in an English speaking company and only have English speaking friends, you will probably not learn to speak French. I live in Germany, and my husband has done exactly that and can barely understand German after 13 years, because he relies on Google translate so much. Whereas I am fairly fluent, not native level, but I can get by, and that's because partially by my own choice and partially by necessity, I've had conversations with the children's schools and Kindergartens, I've been to German toddler groups, I've worked in a German speaking environment. I used to need people to translate for me and now most of the time, I don't.
So I think if you want to work on something like waiting without distraction, or for him to understand when he can and can't ask for toys or cope with pocket money, it probably does help to try to stretch these things a short way. Pick one or two things to target, rather than just vaguely trying to work on everything at once, but it doesn't need to be all or nothing with accommodations. And I agree with what both you and a PP said that once they get dysregulated it's much harder for them to do anything, so understanding that fluctuating capacity is helpful.
But things like waiting and managing money are basically skills, and they can be practiced and worked on by stretching a little at a time and starting small, you don't find growth in the comfortable zone (fully accommodated) and you don't find growth in the stress zone (being thrown in the deep end). Time sometimes helps, so sometimes you can just accommodate accommodate and then one day they suddenly don't need it any more because some other skill/process has developed in the background making that expectation easier for them. Sometimes children who are extremely dysregulated all the time need a LOT of accommodation in order to get them into a more comfortable, manageable place. But if he's generally coping then I think you could probably pick one or two things to try and work on. I just wouldn't work on it primarily with consequences, I'd try to make stepping stones from where he is to where you want him to be, and if it's not working then you need smaller steps.
And also - I don't think you have to be perfect all the time and say the right thing every time. It's much more of a general thing and overall patterns rather than individual moments.