Both employees and leadership suffer when there's a lack of trust at your business. Start building trust through the Employee Management Cycle, which will help keep everyone on the same page and prompt you to re-evaluate as needed.
You may have TONS of excuses why you don't need to pay your techs/installers OT. We've heard it all... but you still do need to pay it. This post outlines how and why to start tracking hours and paying OT correctly if your payroll isn't compliant.
You've got four options when you just can't get your employees to do something you've asked of them... and some of these options are better than others. Read HR Guy's take on how to proceed.
Even as AI gets more advanced, it's still not reliable for Human Resources answers. This exchange with AI outlines a couple of the key flaws, and why you need to consult with a HUMAN for HR compliance questions.

We’re not a generic HR firm. We’re built for service companies with crews, callouts, overtime challenges, and fast-moving schedules. You get practical HR support that fits the real world, not corporate templates.
The HR Guy – HR Support for Service Businesses