It's a bit of all of those things, but I think the most helpful thing has been awareness.
When you make mistakes that creep up over and over, it can be easy to feel hopeless and helpless. Over time it's appealing to want to avoid accountability because trying to be aware and engaged to solve the problem is... Understandably difficult and seemingly impossible. You think of things like, hey I know, I'll plan around this happening again or structure my activities such that it can't occur, but the reality of ADD is that intentions often fail and consistency can be incredibly hard to maintain. You have a good month and resume thinking you're fine.
So, pretending things are fine tends to be a common solution that gradually wears at your psyche. Without having a clear answer as to why the hell you keep messing up you figure you're somehow broken or stupid or whatever. You have no excuses. That's hard to face so you try to keep it out of sight and out of mind. I think when people hit this point it becomes very destructive.
So, talking to a professional opens you up to this realization that yep, you're really bad at functioning in a certain way. However, now you know why, and you realize you have tools (sometimes) that others don't. You're not at an advantage, but you're not purely damages goods either. You can work with this. You've made it this far despite disadvantages, and if you're sensible, you can maintain this or even begin to make some headway.
I began the cliche bullet journal thing, regulating my sleep like crazy, drastically reduced smartphone use, and generally began trying to set myself up for success. It has made a huge difference in practice. Simply understanding myself better has put me more at ease, otherwise.
An important parallel I think of in my life and software is setting yourself up for success. I like to try to write code which, even if (when) it really fucks up, the consequence won't be so terrible. I try to set up my days the same way now. Before I just pretended everything was fine until it wasn't, because I had no idea why it wasn't.
Unfortunately my life is really hectic at the moment, but armed with an understanding of how I'm likely to totally blow it, I've managed to do an alright job working from home and being a stay at home dad for quite a while now. I'm pretty sure that without understanding my condition it would be looming over me constantly like it did before. Now I'm prepared, I guess. I don't live in hiding from a part of myself and there's a lot less shame.
That's a verbose answer but hopefully it makes sense! In a way I'm still making sense of it too, and thinking through it is helpful.