Wattman from AMD can be very confusing for newbies, you can still use msi afterburner and get away with good hashrate if you know what you are doing, it's all about finding the sweetest spot, I'm getting 29.99 MH on my micron rx580 gpu, all you have to do is

Change MV (core voltage) to -162
Power limit to -16
Core clock 1106
Memory clock 2104