Great discussion of web accessibility!
It’s always useful to think about the things you build holistically: not just “how do I make X happen with the least amount of hassle for me personally”, but “does my interface work with existing standards”, “what is the performance cost of doing it this way as opposed to another”, “what if the user’s hardware is not what I expect it to be”, etc.
However, while I do agree with the push for simplicity and adherence to open standards (do you *really* need that fancy JS framework that generates a non-compliant web page, or would a good old HTML form work just fine?), I don’t think you should dismiss the possibilities of modern UI design for reducing cognitive load either.
As someone with ADHD, I love UIs that are minimal, fully searchable, and use instant feedback and progressive disclosure. But this requires fancy JavaScript and breaks the principle of consistency. A basic form which puts all the options in front of you immediately as standard HTML inputs is simple, won’t break any screen readers, and should render just fine on literally anything that has a web browser and was made in the last two decades. But reading through hundreds of options is so tedious that I’d actively avoid it if I can.
Clearly there’s a trade off to be made. We need accessibility and standards compliance, but to some extent the onus should also be on the developers of accessibility tools (especially for commercial browsers and operating systems - say Safari or Chrome) to get on with the times and not push web design back into the 1990s :)