I have 7 of the full grown discus in a 75 gallon planted tank with 30% WC/2times/week without a single problem in the last 2 years.
Like many, I don't like the look of bare bottom tank.
They are roughly 2 to 3 years old.
I had them as sub adult around 4" to start with (in a bare-bottom tank).
To minimize the extra waste produced by unconsumed food, I feed them mainly live black worms and Tetra Color Bits 1 time/day.
I don't have anything else in the tank but a bunch of BN Plecos.
They are too slow and small for discus. They tend to do a better job of cleaning the tank and all. They do poop a lot, but it's good for plants.
Good luck ...