Which professional sports complex occupies the greatest amount of acreage or land area?

The Rungarado 1st of May Stadium in Pyongyang, North Korea, with a capacity of 114,000 spectators is regarded as the world's largest stadium by area.

The multi-purpose stadium on Rungra Island has a land area of 20.7 hectares (51 acres).

Only the Narendra Modi Stadium in Ahmedabad, India, has a bigger seating capacity: 132,000 spectators.

https://wiki2.org/en/Rungrado_1st_of_May_Stadium+Newton

Grand Park in Westfield Indiana is 400 acres (they say 400+).

Grand Park Sports Campus sits on 400+ acres of land in Westfield, IN. It includes 31 multi-purpose fields, 26 diamonds, 377,000 square foot Events Center with 3 indoor full-size synthetic fields, office space, and a full-serve restaurant bar. The campus is also home to the Pacers Athletic Center, and Pro X Athlete Development.

https://grandpark.org/faqs/