Have you at least provided feedback to the managers? Like cold, hard feedback "I cannot work like this, I and my colleagues are going to quit and you're fucked when we do" kinda feedback.
No one ever does this, unfortunately. Getting a group to band together and threaten collective action is something few people even consider - most people I know are scared of entertaining that idea.
It's not about making a collective threat, it's letting management know that the new conditions are making you consider options "up to and including departure", and that you think the other devs may be in the same boat.