People find discus hard to keep, for the same reason my neibors found chickens hard to keep in an open topped pen...we have lots of foxes in our area and they diden't realise that chicken was becoming part of the foxes dinner menu when they added their new pets.....

It's all down to the environment you give them.
Research like crazy untill you can answer any discus question without thinking. Then, forget the reserch and copy an existing set-up, with the equipment used, filter media, water peramiters and maintanance regime. If it works, don't fiddle, just run it

If it doesn't work, you will get a gut feeling due to your reserch, that you should follow to get the tank to work
As stated, stability is key, and I'd recomend a mature tank before you try them. I'd wait untill your tank is 6 months old before adding any
German origin, or locally bread discus are the hardyest to water conditions, so try to get these. If you get wild or Singapore discus, you will need soft acidic water.
My system has about 8X an hour flow through my filters, but with minimal flow in the tank. If has arround a 30-50% weekly waterchange and contains ATM 4 discus, soon to be upped to 6. discus get large, about 9 inches diameter, but are highly intelligent fish. When I approach the tank, my fish come to greet me. When my brother/mother/farther approach the tank, you won't see them for the sand that was kicked up....

They can also tell if I'm approaching to feed, clean or just watch and position themselves accordingly after greeting me
In short, get the set-up right and they will be one of the most rewarding fish you have ever kept. Get the wrong set-up and it will flop
50g is minimum, with 1 discus per 10g as above. Obviously the larger the tank, and the more discus the better. A 50g will hold 5 comfortably. Discus are hard to sex, even when breeding, so you anrn't going to be able to get a ratio of male-to-female. They need good quality food and a clean tank. They settle best into a busy room apparenty
HTH
Rabbut