I have a Senegal in an apartment. However, any single bird is going to need a decent amount of attention from you. They are social creatures.
My kid is loud sometimes but I also have a laid back apartment building. He's mostly loud in the morning and randomly throughout the day. (Think loud and screechy). I think my sennie is louder that most quakers I have met so I'm not sure what your idea of loud is.
Have you volunteered with any rescues? Sometimes that's the best way to find out what species is right for you.
Our neighbors knew well my quaker growing up and we lived in a suburban neighborhood (with yards between them). If some one stepped in my room (very territorial) he could be heard two houses down, while running the lawnmower ect. He didn't schreech often, but Im sure just once and the whole complex would know. He also made a loud "cak" noise for hours, but that may have been behavioral as I was 15 and didn't know what I was doing. He died when he was only six when my brothers ferret broke into his cage. If I thought for a second I could get away with getting a quaker I would.
As for a rescue the closest is 2.5 hours and is dreadful. When we move the closest will be ~six. We have a have of parrot stores, but in the end, as much as they love birds, are trying to sell birds. I'm really relying on experience from other owners online. I am also curious about gcc, but chose to ask more about sennies as I have preferred them upon meeting the birds in person
(but I've only met babies). In the end however I am learning all birds seemed to have there own personalities which is really making this hard
Ive even read a few people having a quaker in an apartment. I'd pay 10k for a quiet, apartment friendly quaker... I just want a bird that I can work with and wont get us kicked out