OpenMandriva Lx 4.1 introduced a new feature: Desktop Presets (om-feeling-like), a tool to customize the appearance of your OpenMandriva Plasma desktop to look and feel similar to other systems you may be used to.
If you were a macOS user and you wish OMLx feeling like Mojave look please perform the following steps:
If you prefer the dark themes, select Use the dark version of the preset if available
Enjoy