Use Assume no preference to randomly assign team bookings
When you use the 'assume no preference' option for the Teams page, bookers are taking to the booking page without selecting a team member.
Combined availability is displayed for all team members. The team member who is available at that time is assigned the booking. If more than one person is available, the booking is assigned randomly. The overall effect of this is that - if all team members have equal availability - then the bookings will be equally assigned.
You might see one team member receiving more bookings to begin with but, similarly to how flipping a coin three times might result in heads each time, over time this will balance out.
If one team member is receiving more bookings it may be that they are more available than the other team members. They can always remove some availability by deleting or adjusting Custom Availability events from their calendar, or by blocking time in their calendar.