If you're not going to quit, and creating a Union could potentially be futile, then collectively employees need to stop bending over backward to hit the metrics until the company is forced to change them.
If the targets are unreasonable and damaging, then stop working so hard and using tricks and short cuts to undermine the situation for you and everyone else.
If everyone starts to show an accurate depiction of work, they can no longer target you individually.
Why should you be responsible to constantly justify the inefficient and inaccurate way we do work to customers who are already in a terrible situation?