It's not possible to sleep monitors independently, but you could setup Monitor Profiles that have each monitor disabled, and then switch between them using hotkeys or the DisplayFusion tray menu. We have a how-to guide on Monitor Profiles here: https://www.displayfusion.com/Discussions/View/working-with-displayfusion-monitor-profiles/?ID=5f41fdbd-bb4f-4052-8de2-a34e47468ec0

If you have any follow-up questions after checking out the guide, please let me know

Thanks!