Grab some ear plugs and settle in, it’s gonna be a long few months for you.
This is a very well known stage in Ekkie development; approach one year old (give or take) they can get LOUD. You can’t really stop it, but it will eventually pass.
Pack your patience.
In the meantime, make sure you aren’t exacerbating the situation and cementing behaviors. Do NOT come running and suddenly appear when the bird screams. No reactions to screaming at all...period. No rewards, no talking, no sudden flurry of excitement if you happen to be in line of sight (excited reaction is itself a reward). Don’t let him out of the cage as a response to screaming.
Your task: endure without making it worse. This is a time where you cannot correct the behavior, but positive reinforcement of the bad behavior can entrench it for life once this stage has passed. THIS TOO SHALL PASS. Could be a few months, be ready. YOU WILL HAVE YOUR SWEET BABY BACK AFTER A WHILE!!!
Also make sure you reward quiet behavior. Have snacks at the ready when birdy is being quiet.
Engage the mind to distract the bird: training! Train targeting, train recalled flight (flying to you on command), train the wave and train turning in circles. These distractions are incompatible with screaming, and can wear out the bird to where his just too darn tired to scream.