RV storage covers like the Camco UltraGuard cover part # CAM45740 that you referenced do not need anything to hook onto on the bottom of the trailer as they actually run straps under the trailer and connect to the other side that way. view full answer...
Based on the description you provided of the issue you are having with your Ultra-Fab Electric A-Frame Jack # UF38-944017 it sounds like the gears inside are worn and require the extra pressure for them to be engaged.
Unfortunately the gears are not available as replacement parts, so the most cost effective option would be to just keep placing your foot on the jack to lower it.
The only other option would be replacing it with another # UF38-944017.
I included a video of the # UF38-944017... view full answer...