You should try the option "Enable Dragging with Drag Lock" in System Preferences > Accessibility > Mouse & Trackpad > Trackpad Options ... Double-tapping and l

You should try the option "Enable Dragging with Drag Lock" in System Preferences > Accessibility > Mouse & Trackpad > Trackpad Options ... Double-tapping and leaving the finger on the trackpad lets you drag the window or other item until you short-tap again. Drag lock even allows you to lift your finger and continue dragging from a different position on the trackpad.