NOT the apex predator
You’re right.
That would be the Orca, the Killer Whale( a dolphin actually).
A shark is a big, dumb set of teeth swimming around looking for a meal.
Killer Whales are highly intelligent social animals with a complex brain and a language. A male Orca can grow to 30 feet and weigh 9 tons.
If just two of them decided it was time to start hunting humans NO ONE would want to go into the ocean.