male/female aggression...

You may have seen this , but check out the female uropthalmus (dark mark in the dorsal, and sub dom males for that matter) in my video of Eden Cenote in Mexico.
The dominant males were almost always in caves and only seen when they came out to feed or attack. If a female wasn't receptive she was driven out. Most females and sub dominant males are in large shoals in the open, with plenty of room to escape.
Even most large aquariums are mere puddles compared to normal habitat.
https://www.youtube.com/watch?v=Zb3v0VJTg5c

The caves in the cenotes seem to be mostly naturally occurring, with some bit of renovation.
Seems to me females avoid the big males until ready, then the females choose, there's a little sparring and it either clicks, or doesn't.
I believe only the most fit males live to breed.
I have never snorkeled in waters with Oscars, or other Amphs, but I have with Jack Dempseys. The JDs seem to guard an area of about 4' X 4' X 4' (@ 250 gallons) and drive any other cichlids out. Almost all breeding JDs I saw, had wounded, fungus covered jaws and lips from sparring with females, or other males. Check out the large area the mated pair are defending at just over a minute in the video below (its over 5ft deep).
https://www.youtube.com/watch?v=e8OVy3JKxcw
and below, the fungus covered jaws on the dominant male below defending a cave.