In a heavily planted tank, I would stay away from Cichlids in general (especially Oscars). Most species of Cichlid will want to rearrange your tank to their liking, which includes uprooting plants and digging in the substrate. If you’re trying to avoid large weekly water changes, then Discus are probably out of the question too. While some very recent strains have been a little hardier, as a generality, Discus require very warm, very soft, very VERY clean water. This will leave you a very small selection of plants, and a lot of work trying to balance plant nutrients with a demanding fish.
For a colorful fish that is well suited to a planted tank, and is less demanding than discus, you can go for Angelfish and Rainbowfish. They can both tolerate slightly lower water temps, they won’t dig in or eat plants, they are colorful, and they can tolerate a wider range of water parameters. I would round the tank off with some Otocinclus, Cory cats, and Nerite Snails.
Edit: I also agree with what Riza said about the tank being on a table. At 8lb / Gallon, a 90 Gallon tank is at 720 lbs of water alone. Add the tank itself, substrate, and hardscape, and you will be exceeding 1000 lbs for sure. That better be one damned good table lol.
