You may already realize this, but one clarification I would like to emphasize that was mentioned in passing above, is that in Linux the window manager/desktop environment is separate/configurable/changeable separately from the distribution. This took me a long time to wrap my head around when I first moved to Linux since I was used to it all being the same thing in the Windows world… Saying “Windows 10” implied a certain desktop experience, a certain OS kernel, and certain software support.
In the Linux ecosystem though, your distribution will often come with a default window manager, but they are actually separate things. There are many linux distributions that can/do use Gnome or KDE as their window manager. Manjaro, Ubuntu, Elementary, Cinnamon, and Pop!_os are all distributions known for having an emphasis on approachability for more novice users. This means they come with a default graphical/screen reader compatible window manager, install wizards, etc. Each respectively has a default window manager, and will look very different, but they are all “linux” at the core OS level.
Depending on the accessibility needs of your specific community though, you may find a particular window manager and ecosystem works best for you. For example, if using a mouse is difficult, you may actually have a better experience with one of the more “advanced” keyboard-focused tiling window managers like Sway. If you find KDE works best, but want the wide software compatibility offered by Ubuntu, you can use the Kubuntu distribution instead, which is a flavor of Ubuntu that installs KDE out of the box instead of Ubuntu’s usual Gnome. You could “create” Kubuntu from a regular Ubuntu install by manually installing KDE and removing Gnome, since both are available in the Ubuntu repositories, although this would probably require interacting with the terminal quite a bit.
All this was to say that the distribution really determines what package repository you are pulling software from, and most of the major repositories support a variety of different window managers. If you search for “Ubuntu accessibility settings” you will find forum posts talking about settings in Gnome, Ubuntu’s default window manager. As indicated by Kieran_Levin above, you’ll often find more information by actually searching for “Gnome accessibility settings” instead, since then you will get input from users of many distributions using Gnome, and the Gnome team are actually the ones implementing and designing these features.
Welcome to the world of Linux! It can be a lot to learn at first when switching, but comes with great power and flexibility in the long run!