Hi Riley,
Greetings from Syncfusion support..!
Currently it is not feasible to meet your requirement ‘add label in empty cells’ at our end, we have already considered this requirement as feature request which can be tracked through the following link.
The feature will be included in our Volume 3,2021 release which is expected to be rolled out by the end of September, 2021. We would appreciate your patience until then.
Regards,
Praveenkumar