if i am looking for something in between whatsminer m21 and s9 what would you recommend? if my budget was in between these 2 machines.
Nothing really falls in between, the S9 does on average 80w/th with custom firmware (as low as 72w on some gears if downclocked really well), the M21s is about 60w/th, there is nothing that does anything above 60w and below 70w which I would recommend to anyone, if the M21s are above your budget, get S9i/S9js, or you can always mix two gears, maybe fill 30kw with M21s and 70kw with S9s, that will give you an overall (in between) option.