While you are able to change the values in the macOS settings pane it should not affect the settings.

Try closing the settings window after changing the value and open it again. It should be back to the value you defined.

Thank you @lawinski you´re right! 🙂

despite the correct settings, on all test devices that have received the config profile, the screen only locks and goes black, the screen saver does not start. can anyone help here?

try this as script and set parameter to 1 or 2,

#!/bin/sh
## get current user
op=${4} #op=1 then photo , op=2 then Custom
user=`ls -l /dev/console | cut -d " " -f 4`

## get macOS version(s)
osMajor=$(/usr/bin/sw_vers -productVersion | /usr/bin/awk -F"." '{print $2}')
osMinor=$(/usr/bin/sw_vers -productVersion | /usr/bin/awk -F"." '{print $3}')

## set key items for screensaver
/usr/bin/sudo -u $user /usr/bin/defaults -currentHost write com.apple.screensaver CleanExit -string "YES"
/usr/bin/sudo -u $user /usr/bin/defaults -currentHost write com.apple.screensaver PrefsVersion -int 100
/usr/bin/sudo -u $user /usr/bin/defaults -currentHost write com.apple.screensaver showClock -string "NO"
/usr/bin/sudo -u $user /usr/bin/defaults -currentHost write com.apple.screensaver idleTime -int 300 # wait time before start Screen saver in seconds

function iLifeSlideShows_config() {
/usr/bin/sudo -u $user /usr/bin/defaults -currentHost write com.apple.screensaver tokenRemovalAction -int 0
/usr/bin/sudo -u $user /usr/bin/defaults -currentHost write com.apple.ScreenSaverPhotoChooser LastViewedPhotoPath -string ""
/usr/bin/sudo -u $user /usr/bin/defaults -currentHost write com.apple.ScreenSaverPhotoChooser SelectedFolderPath -string "/Library/Application Support/JAMF/bin/Foldername"
/usr/bin/sudo -u $user /usr/bin/defaults -currentHost write com.apple.ScreenSaverPhotoChooser SelectedSource -int 3
/usr/bin/sudo -u $user /usr/bin/defaults -currentHost write com.apple.ScreenSaverPhotoChooser ShufflesPhotos -bool "false"
#Name of screenshot neet to mention in styleKey -string
#/usr/bin/sudo -u $user /usr/bin/defaults -currentHost write com.apple.ScreenSaver.iLifeSlideShows styleKey -string "Custom"
/usr/bin/sudo -u $user /usr/bin/defaults -currentHost write com.apple.ScreenSaver.iLifeSlideShows styleKey -string "Classic"
/usr/bin/sudo /usr/bin/killall -hup cfprefsd

}

if [[ "$op" == "1" ]]; then
/usr/bin/sudo -u $user /usr/bin/defaults -currentHost write com.apple.screensaver moduleDict -dict moduleName -string "iLifeSlideshows" path -string "/System/Library/Frameworks/ScreenSaver.framework/Resources/iLifeSlideshows.saver" type -int 0
iLifeSlideShows_config
elif [[ "$op" == "2" ]]; then
/usr/bin/sudo -u $user /usr/bin/defaults -currentHost write com.apple.screensaver moduleDict -dict moduleName -string "Customfile" path -string "/Library/Screen Savers/file.saver" type -int 0
fi

sudo killall -hup cfprefsd
exit 0