Is it permissible to demand the cost of renewing the residency permit for eight years, or to take it secretly, given that the establishment does not pay it to this worker, unlike the rest of the workers?

The worker is an employee of the employer, and the wage between them is determined by agreement. So, if they agree that the worker bears the costs of residency procedures, or if there was no agreement and the law obliges the worker to bear them, then there is no harm in that. It is not considered injustice if these fees are not taken from some workers, as long as the worker has voluntarily agreed to it. He is not entitled to take anything from the employer's money unless he deserves it, but he has the right to demand equality with others. If the employer does not agree, then he has the right to refuse to renew the contract.