I didnt test GNOME or KDE for accessibility but I know KDE 5.27 had various different zoom features while GNOME doesnt.
Orca runs on both but no idea where better.
Both are using Wayland on Fedora and that is pretty problematic poorly, as all apps are different and I assume many dont support the correct portal/API/push service for screenreaders.
The rest seems integration. KDE and GNOME use Packagekit on traditional Fedora.