SUMMARY mismatch between default value of ScreenReader enabled on kaccess and kcm_access looks like fixed in https://invent.kde.org/plasma/plasma-desktop/-/commit/4264fefb9e122ebc22aa79cd336463dd3c1816cb but needs backporting to release branch Linux/KDE Plasma: Nixos (available in About System) KDE Plasma Version: 5.27.6 KDE Frameworks Version: 5.107.0 Qt Version: 5.15.9
That was done a year ago and should definitely be on the Plasma 5.27 branch. What problem are you seeing happen here?
The relevant commits are part of Plasma 5.27.7