Is it legal for exempt managers to take over an hourly (non-exempt) job after hours in Ohio?

I work for a company in OH that has an hourly employee who handles tasks from 8-5, and then at 5:01 the on-call manager takes over the role until 8 am the next day when the hourly employee returns. The managers are salaried so they get no OT to do the exact same job that the hourly employee does. It’s like they want to do a loophole to avoid paying overtime so they drop it on the managers and call it on-call when it’s really mandatory unpaid overtime to the tune of 90+ hours a week on the managers who don’t make any extra money.

Also, they require hourly employees to complete company training on personal time (unpaid) even though it’s for company benefit and aligns with their job within the company. That doesn’t sound legal to me.

Location: Ohio