I have a problem working with freelance clients that want me to record my screen with screenshots every 10 minutes as part of the time tracking and billing.

This is way over the top. Even the taking screenshots and tracking keyboard and mouse activity is too much. It's very easy to tell if a dev isn't being productive or doing their part especially once there are several devs working together.

I bet the true problem is they are expecting too much from the devs and had unreasonable deadlines so it seemed like the devs were unproductive because they missed those unrealistic deadlines.