Benz MBUX 2021 KSW V2
This theme was introduced in update Ksw-Q-Userdebug_OS_v3.9.4-ota, therefore it might not be available to activate on earlier firmwares.
To make this theme available for selection in your factory settings, you might need to modify your factory_config.xml file. Find the <SupportUIList /> section and add the following line: <Item id="1" name="Benz_MBUX_2021_KSW_V2" display="Benz MBUX 2021 KSW V2" />. More information and examples can be found in factory settings section.