adult adhd symptoms are vastly different than childhood adhd and many people suspecting they might have adhd, might actually have it.
I had even stereotypical symptoms as a child but just wasn't tested.
Mention you've been struggling with these symptoms for years and there has been a lot of discussion online about, you're not sure if you have a real case or something else, but you'd like to do some evaluations.
They'll usually tell you if they'll do that, or not, and could often refer you to someone who would.
Speaking as an almost-40 whose ADHD was untreated until recently: Contrary to your suggestion, being almost 40 did not make the process of navigating the medical labyrinth (Canada) to get assessed/treated any easier. Almost like I had an attention disorder or something.
if it was easy, id have sought help decades ago. love how people think "oh man its such an easy solution" when it is, in fact, a lot of work. My fiance had periods that lasted months, and not a single doctor would even consider looking at root causes "have you considered that maybe its all in your head?" getting the right treatment is in no way easy, especially when its a mental disorder that you can "cope with".
The first time I went to the psychiatrist to ask to be tested for this was three years ago. They told me I can't have it, because if I did I wouldn't be able to maintain a job, and being able to do good at work, especially as a dev, should be impossible. They said I'm depressive and put me on SSRIs that fucked me up for 6 months.
I was depressive, been like this ever since I was able to reason for myself and figured out that neither me nor others know what the f* this whole thing I'm waking up is, but my depression is my always-there companion, that keeps me humble and thoughtful of life. What the SSRIs did to me was very different, and much, much worse.
Adult testing is a thing, and I'm not mad at all for not getting a diagnosis earlier, I'm just grateful that it happened at all.