Is it permissible for officials to withhold due bonuses and incentives under the pretext of inability or by demanding extra working hours to obtain them?

If the institution's regulations stipulate the right of those who exerted effort to receive rewards, and they cannot obtain them except through that method, then there is no harm in that, according to the preponderant opinion of scholars. However, if the institution's regulations do not stipulate this, then it is not permissible for you to receive payment for hours you did not work.