Welcome. I have just one Quaker, Ralph. I do know a little about how things can go with two parrots of the same kind though. You might want to consider separate cages on a long-term or even permanent basis. Most parrots appreciate having their own space. Your current Quaker and a second one might become best buddies, or they might take a dislike to each other, or anything in between. Lots of one-on-one time with each parrot separately is important to keeping them bonded to you and not exclusively to each other (another reason separate cages are a good idea). Your current Quaker might be happy to have a new friend, or he might resent having to share his home, and you, with another parrot. All these things are next to impossible to predict. It's possible that your Quaker might call less, or you could end up with two Quakers endlessly squawking back and forth. It all depends on the individual personalities of the birds and how they feel about each other. Maybe someone with actual experience housing two QPs together will chime in with some better advice for you.
Doing lots of research is the right way to go. Of course, if you were to choose another type of parrot than a Quaker, separate cages are a must.
I can comment on having a QP and a different kind of parrot at the same time. I rather unexpectedly adopted an African Grey parrot a few years after I got Ralph. Scooter the Grey was fascinated by Ralph, as long as he kept his distance. He once landed on top of Scooter's cage and she was going into attack mode as I got Ralph away from there. If Ralph was in his own cage, or outside of it but not too close to hers, she loved to watch Ralph. Sometimes I thought that she was learning how to be a parrot from watching Ralph. On the other hand, Ralph was mostly indifferent to Scooter. Once in a while he would look to see what she was doing, and occasionally they would chatter back and forth, but Ralph mostly went about his own business. I never let them interact with each other outside of their cages. I was pretty sure that wouldn't have gone well. After Scooter passed away last fall, it was obvious that Ralph missed her and sometimes he seems to be wondering why there's no other parrot here anymore, but on the whole, I believe he prefers being an only parrot. He would probably accept and tolerate another parrot if I ever got one, but that's not in my plans for now.