Idiom or expression for no-one wants to help do a task, but everyone is ready to criticise after the task is completed
put up or shut up TFD an idiom
To take action or steps to resolve something that one dislikes or else stop complaining about it.
As in:
2003 New York Times Iraq's unexpected willingness to grant access to United Nations weapons inspectors presented American intelligence with a challenge to put up or shut up.