UsefulCommands aims to add commands that minecraft should've had in the first place. UsefulCommands doesn't overwrite any vanilla commands so there should be no conflicts when adding to your server. To request features go to the issues section and add the feature request tag or bug report tag if you're reporting a bug.
Support discord: discord.gg/QmJGMAKDXX
Don't use UsefulCommands with essentials it is meant to be a replacement to essentials