Unfortunately, Florida allows employers to impose overtime work, and there is no limit to the number of hours they can require. Unless your employer is violating employment law, safety regulations, or a contract through mandatory overtime work, you cannot oppose it.
OT is based on cumulative over the week, not daily. Over 40/week is OT.
The state of Florida has no daily work hours limit, so employees can work as much as they want. However, if an employee works more than 40 hours in a workweek, they are entitled to overtime compensation — unless they are exempt.
In short, there are no job-protected options for refusing overtime work under Florida or federal law. In an at-will employment state like Florida, if you are an at-will employee, you can refuse to work overtime, but your employer can fire you for doing so.