I’ve seen a lot of posts about Az being controlled by the Metatron but I don’t buy it.
I’m fully on board with Aziraphale making stupid decisions for what he believes is the greater good. We’ve had evidence time and again of him wanting to get Crowley back on the side of angels so he’ll be safe. “they’ll destroy you”/“they’ll kill you” was his biggest fear all through S1 and that fear hasn’t gone away, especially now the neutrality protection has gone from the bookshop and Heaven and Hell can both get in.
You’ll notice he said “I don’t want to go back to heaven” until the moment the Metatron tells him that it means he could guarantee Crowley’s sanctuary and safety. And this is not ten minutes after the rest of heaven’s archangels were planning on wiping Aziraphale completely from the book of life and leaving Crowley alone? The Metatron didn’t have to threaten Crowley. The threat has always always been there. Aziraphale didn’t choose death because he’s predictable.
Trouble is that the Metatron knew Crowley wouldn’t want it (he’s always been an independent one, going his own way, asking questions) and is using this as something to drive a wedge between them. Because the Metatron fully admitted that “we’ve kept track of your history” and as Gabe said re. Armageddon “at least we know who’s fault it was” that it stopped.
Together, Crowley and Aziraphale have stymied Heaven more than once. Together, they produced a miracle that exceeded the power of the Supreme Archangel and could raise the dead 25-fold. Together, their interference/cock-ups led to the failure of Armageddon and Heaven doesn’t want to risk that when they’re working up to the big one, The Second Coming.
They know Aziraphale and Crowley together would be a liability. They needed them separated by whatever means and they have it. They knew Aziraphale would want to do good - everyone knows Aziraphale is a good guy. Even Gabriel, when his memory was gone, went straight to Aziraphale because he instinctively knew this is someone who would protect him. And everyone knows that Crowley is the rogue angel. The Metatron clearly knew him and described him as someone “who always wants to go his own way”.
The Metatron played on both their fears. He also played on Aziraphale’s belief that Heaven can still be good: he came in just in time to save him from erasure from the book of life, he implied that he’s much more like Aziraphale by bringing him nice sweet things and encouraging him to imbibe them, he offered safety and protection for Crowley to keep him out of harms way. But simultaneously, he slammed Crowley’s big red horror button at the idea of being under Heaven’s thumb again. He knew exactly what he was doing.
TLDR: Aziraphale did what he always did. He’s a guardian. He’s doing what he feels he needs to in order to keep people safe. And Crowley did what he always did by rejecting Heaven. The Metatron used that and pressed his and Crowley’s buttons to make sure he split up the dream team to make sure the next Armageddon isn’t interrupted by their interference.