There is no point to negotiate, or to sue them.
Start job seeking ASAP. Do not quit, but work less hard. Insert delays into your responses. Before you commit code, take 30 minutes to study some subject or seek job.
Drop productivity, but no engagement (that is metric that matters). Still answer client calls at 4 am, pretend you work 12 hours a day etc... They will shout at you for a while, but after couple of sprints, requirements will adjust and be less demanding.