With the latest firmware, Snapmaker now presents itself as Grbl and not Marlin.
See this thread: Announcement: Snapmaker firmware updates have affected LightBurn usage
You will need to add a new device by importing the corresponding .LBDEV file from this page: Using Ray/Artisan/2.0 with LightBurn | Snapmaker Wiki
It’s unclear to me, why a configuration file for your Artisan with the 10W module is missing and if you can just use the 20W one instead.