Welcome Buhg,
Screaming is a very very hard thing to take. I have loud quakers, and my new guy is a screamer. And it is torture, I agree.

But Screaming is because the parrots needs aren't being met, and then it becomes reinforced and a habit. Plus they do like to make noise, some species more than others.

I've worked with a lot of rescues . And they have been shoved off to back bedrooms, garages, basements, outside, hours and hours of isolation, and they go insane and self destruct.

So I don't want you to feel I'm attacking you, i just talk blunt and spell out facts. But I have tons of empathy for your situation. As stated above im living this torture myself. And its a hard habit to rehabilitate.

That being said, this is a terrible situation for a highly intelligent, highly social , very active creature. In isolation for the majority of the time, with at best 2 hours of out of cage time.

Now you are home and forced to face his acting out and unhappiness. If you aren't going go be able to put in a lot of time and work, then decide now if finding a home that you clearly educate them on his Screaming might be best.

I have links to articles to help with screaming. I've had success in the past with screaming. Usually by increasing out of cage time to around 6 hours daily. Patterning to soothing music, foraging, increasing social interactions, flying and easy tricks training.
But I feel like a failure myself with my current screaming quaker, who is screaming now. I knew he was a screamer at the petstore, and I thought my past tips would work. But his default is too make a lot of noise( not exactly screaming, but feels like it) he spends 8 hours out of the cage, has lots of foraging, other parrots, and in the middle of the action at home.....i have decreased the duration greatly tho, and im trying to form new habits for him. So I'm in the middle of it too. I really understand how disrupting, and insanity inducing it can be....

I'll go get the links now

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"When you want to help people, you tell them the truth. When you want to help yourself, you tell them what they want to hear. "Thomas Sowell