iMac 2019 hard disk performance

Hi

I recently bought the iMac 21.5" retina MRT32T with mechanical disc (1TB)

Mojave is incredibly slow as per my feeling:

I have other two iMac with mech. disk - 27” 2012 and 21.5” 2015 - performing really better with El Capitan. 

with the Blackmagic test it does not exceed 70MB / s read:write .... is there anyone else experiencing the same disk performance?

Regards