Do you need a reference from this job? If not, it's better to do the minimum and keep taking their money. Let them pay you to prepare for your next job. Unless

Do you need a reference from this job? If not, it's better to do the minimum and keep taking their money. Let them pay you to prepare for your next job. Unless a company is showing you loyalty in a tangible way, you don't owe them anything. Fight back against the overtime. What are they gonna do, fire you? Then you get your free time.