Is this even possible with a controller? I’ve gotten so used to running with a controller that I really don’t want to switch to kbm just to do this one section optimally

Sadly no from what I can remember watching my old PBs again. Back when I was running this game I was using a Fightstick; I'd just try to adjust the killing order to get the ones in the back row that would appear first and then throw things forward so at the very least it wouldn't lose as much time that way.

Its broken with dpad only, that's why fightsticks don't work. if you use the analogue stick on your controller then it works, although i reported this as a bug a long while back so it should be fixed in the dlc update