SUMMARY
Currently accessibility settings feel very unhelpful as it does not include many much-needed features and KDE settings in general make it extremely hard to find the accessibility features needed. I will try to explain why and what needs to be done

As a visually impaired person myself i heavily rely on accessibility tools like magnifiers, Dark mode and more. Whenever I install or try new distro or DE My first instinct is to search for accessibility > Zoom and mostly i never had a problem finding the tool i need by myself on first try with most other DE's and other operating systems like windows. But, with KDE my first experience was extremely painful as if i search for Zoom anywhere search results won't show something like zoom or accessibility instead it would show Desktop Effects which makes it completely unintuitive and as i cannot read without zoom the UI was extremely confusing to me. So, i had to ask someone for help and they did not know anything about KDE or linux in general, above all people lack patience they always expect to find things instantly as such they would just read whatever I ask them to read and when they read Desktop Effects again and again it just made things worse and since zoom is not immediately visible when i asked them to see if they can find something like zoom, they said "NO". which made things extremely confusing with all my confusion i kept insisting it should be under accessibility as zoom is an accessibility feature. Then it took me two days to finaly figure out where Zoom is

Even now after knowing more about KDE and playing around with settings sometimes i still feel like things are really unintuitive when it comes to accessibility things are very much scattered

FEATURES REQUESTED
It would be nice to see more accessibility features added to KDE. The following features should either be newly implemented or existing features should atleast be placed under appropriate sections under accessibility settings. Existing Kwin desktop effects should either be moved to settings > Accessibility or at the very least get shortcuts linking to the necessary features

These features should also be easily searchable from anywhere on the desktop. 

For visually impaired users
Zoom - Fullscreen zoom, Lens Zoom and Dock
Color inversion
High Contrast - high contrast with ability to switch between high contrast "Light" and "Dark" themes
Font Size adjustments - Options for font sizes ranging from Very Small to Very Huge with preset font sizes
Color Correction 
Grayscale
Visual effects and animations - Ability to enable or disable visual effects like animations, transparency and more
Mouse pointer Adjustments
Screen Reader

For Hearing impaired
Mono Audio
Captions
Visual feedback

For physically impaired
Speech to text
Keyboard adjustments

And more required accessibility options with a cleaner intuitive interface and searchable properties for accessibility tools. 

ADDITIONAL INFORMATION
Issue 439840 mentions similar issue 

Although i appreciate the fine-grained controls KDE offers When implementing these accessibility features, please try to focus on providing intuitive presets and defaults. Wich would offer a much better UX for people with disabilities compared to them trying to figure out and finetune every aspect of the desktop.