Aquatic ape is an oxymoron. Apes cannot swim. That is why the bonobo can keep the gorillas and chimpanzees away from its territory. The bonobo lives on the opposite side of the Congo River from the common chimp and the gorilla. The bonobo's habitat is as good as that of the gorilla's and if not for the river keeping the gorilla and chimp away, the bonobo would not be able to maintain its territory, since the gorilla keeps the chimp away from its territories though brute strength and the chimp is also territorial.
Yes, some gorillas have been seen wading on 2 legs in shallow water while looking for food. Wading on two legs is very different from swimming. In fact, a swimming and diving gorilla would not be wading. It would almost certainly be swimming on 4 legs. No Olympic swimmer swims by walking along the bottom of the pool. Humans swim by having our backs parallel to the surface of the water, not perpendicular to it.
The aquatic ape theory is an attempt to explain why human ancestors evolved to walk on 2 legs instead of 4. A far more likely reason why our ancestors walked on 2 legs is that many animals such as squirrels, rabbits, bears, and meerkats stop periodically stand on 2 legs to look out for danger. Since humans evolved on the dangerous African savanna, our ancestor would be safer if they can look out for danger all the time by walking on 2 legs. They do not have to stop periodically to do so. It also frees their hands so they can carry branches and sticks to defend themselves against predators.
The aquatic ape hypothesis is all wet.