Once you get the job, most workplaces simply just want you to get the job done and are fairly flexible.
Need to wear noise canceling headphones or hole up in a conference room to write some code in a distraction-free environment, etc.? Been in the industry for 25 years and that's never been an issue.
Mentioning a label like ADHD to an employer is IMO useless at best and career suicide at worst. Most commonly it sounds like you're making excuses. Best case scenario is that they're sympathetic, but, the label "ADHD" still does not tell them what you actually need. Even if your manager has diagnosed ADHD as well that doesn't mean her needs are the same as yours. So why even mention the label? Tell them what you need -- or better yet, when it's feasible, just do it the way you need to do it.
For example, working on a teeny tiny laptop monitor exacerbates my ADHD. Shuffling windows around really breaks my flow. So I like big and/or multiple monitors. If I have a workplace tech budget I use it on big-ass monitors or I simply bring my own.
There are physical and mental health diagnoses for which I wouldn't give this sort of advice. And yeah, the world should be different.
ADHD needs to be understood and destigmatized and I do talk openly about ADHD (like now) but it's just something I don't volunteer about myself in my professional life.
n.b. when I say "career suicide" I could have used a better choice of words. I wouldn't ever say that mentioning would torpedo your entire career. But it might be bad for your career at a given company IMO/IME. Depending on who reads it and how neanderthal their views are.
Selling yourself is a game, and the ones "buying" you dont have the cognitive head space to make difficult decisions across many candidates. They will always choose the mentally easier option.
The "game" is that you have to as quickly as possible figure out exactly the mental model of what it is they want, and frame yourself as that. All the parts of whether you or they actually fit each others needs must be done within that dynamic. You cannot explicitly mention negative qualities, you have to infer whether they will be accommodating.