m8
people were complaining that they had to waste time and complete each map on all 4 difficulties, instead of them all unlocking automatically if you complete the map once on highest difficulty. (And yes those complaining were old players)
So devs changed that to 2 achis, one completing the map and other completing the same map on the highest difficulty.....
So now you suggest throwing the "QoL" under the bus and add back the one thing that some people didnt want, is to waste more time again to achieve all achievements.