First time vacationing with the family since Covid...

First time vacationing with the family since Covid. Kids were super excited as our schedules never allow us to travel. Showed up not knowing you need a reservation for pool. Then try to make one and the rest of the night and morning already booked. 1 or 2 people booking entire pool for multiple time slots. Kids are now crying and trip is ruined. Will not stay at a Marriot again. There was nothing the staff said they could do. Thanks for nothing.