And this is where you lost me as you seem to imply that I'm thinking mental illness doesn't exist, which as someone who suffers from rather severe depression I can tell you I don't doubt the existence of neurological issues

That is honestly a relief and why I mentioned that I was hoping that I was misreading you.

this idea that it's just all people who are being under diagnosed and that there might not be environmental issues that are at play ...

I do not think that it is likely one or the other but a combination of multiple things. I also strongly suspect that there are environmental issues at play too. With the well-established like between lead poisoning and aggressive behavior (not to mention the slew of other neurological problems), I strongly suspect that we're likely to see similar from microplastics or another widespread exposure that we're not yet aware of. And that's just chemical environmental exposure. Not even touching on harmful social exposures. The high-stress environment of the modern world is extremely harmful to physical and psychological health.

... rising the numbers means you also think that brain chemistry is a thing to be controlled and fixed at will of those with the chemicals to try them out on other people's brains.

I think of it as a spectrum running from "needed to survive without harming self or others" to necessary for harm reduction/mitigation due to neurodivergence that makes functioning in modern society very challenging. It's not that there's an "ideal" neurochemistry or neurophysiology but that there are neurobiological phenotypes and conditions that are either not well-adapted to modern society (or, in some, extreme cases, any society). Use of chemical and other available therapeutic means allows for such individuals to survive or thrive in an environment that is not ideal for them.

But man does it feel insane to be taking synonymous drugs that were taken during war time to keep your gunners alert for air raids to keep up in your work life balance.

Absolutely, it does. Medicine can be a bizarre thing. Similarly, like I hinted earlier, nitrogen mustards, as in "mustard gas" were the first chemotherapy agents for cancer treatment. Mustine (chlormethine) is still in actively used for this purpose.

And excusing it away by saying their is a perfect version of a brain that needs to be achieved by taking this drug causes an emotional response in myself.

Indeed. There can indeed be some denial, etc but, I suspect that a lot of it comes down to defensiveness due to societal issues. When people make a comparison to illicit stimulants, it often comes back to things like the ongoing shortage that has impacted a lot of people with ADHD. The shortage is caused, pretty definitively, by the DEA overcorrecting their enforcement of controlled substance, after they did fuck all about opioids. Amphetamines are a convenient target to "show that they're doing something" because they sound like meth and are used to treat disorders that are either rare or not taken seriously.

Loose enforcement of the past allowed pill mills to thrive and supply the illicit market. Now, they've clamped down, causing measurable harm to those legitimately prescribed. They don't care because they're just in it to justify their budget increases and get camera time.