It's Animal Kingdom for sure.
Let's do some conservative calculations. It's hard to find estimates for how many daily visitors Animal Kingdom sees so I'll just do a broad calculation- approx. 8,770,000 visitors in 2023 = just over 24,000/day. That feels fair. I can go on the Disney World website and get a bundled deal that works out to $89/day for adults, or the same ticket at $59/day per kids. Let's stick the daily ticket price at a very modest $70/day. This should hopefully account for people super-discounting and people not-at-all-discounting.
24,000 people daily x $70 = $1,680,000. In ticket sales alone. That's not including food, souvenirs, associated resort stays, photos, fast pass sales, or the quadrillion-and-one other ways that Disney can get a dollar out of you.
(in ticket sales alone that'd be- again, I think a pretty conservative- $613,200,000 yearly.)
these numbers are far from gospel and I dare not imagine what their operating costs are. but i'd be hard-pressed to find a zoo with that much income elsewhere.