Crew Management is a feature that allows creating and managing crews of multiple service resources who share the same service appointments[163]. The Preferred Resource service objective is ignored for active Crew Members because it only applies to individual resources and not crews[164]. Capacity-based scheduling is not supported for Service Crews because crews do not have capacity limits and can be assigned unlimited service appointments[165]. A service resource can be a member of multiple crews and can switch between them depending on their availability and skills[166]. Salesforce Field Service does not consider the Recommended Crew Size when assigning appointments because it only considers the Required Crew Size which indicates the minimum number of crew members needed for a service appointment[167]. References:
https://help.salesforce.com/s/articleView?id=sf.fs_service_crews_overview.htm&type=5 https://help.
salesforce.com/s/articleView?id=sf.fs_service_crews_limitations.htm&type=5 https://help.salesforce.com/s
/articleView?id=sf.fs_service_crews_limitations.htm&type=5 https://help.salesforce.com/s/articleView?id=sf.
fs_service_crews_create_edit_delete.htm&type=5https://developer.salesforce.com/docs/atlas.en-us.api.meta
/api/sforce_api_objects_serviceappointment_requiredcrewsize.htm

Explanation
Operating Hours define when service resources are available for work and when customers can book appointments. The Time Slots for Appointment Booking setting determines how operating hours are divided into time slots that can be assigned to service appointments. The Maintenance Plan for the Account or the Due Date of the Service Appointment do not affect operating hours, but are used to generate and schedule recurring work orders. References: https://help.salesforce.com/s/articleView?id=sf.fs_operating_hours.htm&type=5
https://help.salesforce.com/s/articleView?id=sf.fs_maintenance_plans.htm&type=5