What complex has the greatest capacity of individual ticketed seats?
I guess this could be divided into two answers, indoor venue and outdoor venue?
This is “ticketed seats” only and can not include general admission. So while you can count all the grandstand seats at someplace like Daytona Speedway you can’t include infield seating since it is general admission.
This can be a venue for sports, arts, whatever but you need to be able to buy a ticket for an individual stationary seat to count.