IMO, unless the psychiatrist is a specialist in a specific neurodivergent condition, I think that the general wisdom is to collect data, make a hypothesis, start treatment (at a low dose) and gauge reaction. If the treatment for the suspected condition improves the symptoms of that condition, then it's reasonable to assume that the hypothesis is correct. If it doesn't have the desired effect, try a different treatment and reassess.... It may be that your biological makeup is simply more or less susceptible to the treatment, and a different treatment will be more effective. Aka, not all drugs work for people as well as they should.
One example I can give for this difference is between me and a friend. My friend got a heavy dose of prescription strength naproxen, a non-steroidal anti inflammatory usually used for muscle/joint pain. Even at the insanely high dose of the prescription, it didn't have any effect for them. I picked up some over the counter, not-even-the-strongest-otc version of the same. Just regular strength stuff off a shelf in the pharmacy. Maybe 1/10th as "strong". I take one, and I'm so relaxed that I start to feel weak. Meanwhile, other non steroidal anti inflammatory drugs like ibuprofen work fine for them...
It's all dumb biology stuff.
Anyways, I think there's been too much backlash against doctors for throwing diagnosis around without the proper due diligence to support making that diagnosis. So IMO they're being more careful before handing someone a confirmed diagnosis.
Even my own doctor said, and I can quote him, that "[my symptoms] are consistent with mild ADHD".... It's not "you have ADHD", it's merely stating that there are similarities between my symptoms and ADHD symptoms.
It's a whole thing.
Welcome to the fold. Here's your fidget toy, and complementary squirrel.