There is no issue with operating the MAX98307 without a load. In addition, you may add and remove a load while the part is in operation.
MAX98307
Production
The MAX98307/MAX98308 fully differential mono Class DG multilevel power amplifiers with integrated inverting charge pumps offer highly efficient, high...
Datasheet
MAX98307 on Analog.com
There is no issue with operating the MAX98307 without a load. In addition, you may add and remove a load while the part is in operation.