For the time being, working hours are not supported to be edited in bulk in out of box features. Even with the work around of applying the work hour template to multiple records, this is situational in its usage as the work hour template will overwrite existing calendar or work hour of the records, including even the time off.

Hence, it will be beneficial for users to be able to edit working hours in bulk as a core feature instead of using custom APIs as this will greatly enhance the member time management experience and workflow.