Read my post #18 here (and the sub-post linked)
https://forums.d2jsp.org/topic.php?t=107327803&f=148&o=10If you can understand those 2 posts, you'll be able to avoid making the same mistakes most people still do over and over.
Here's the proper build for optimal playstyle:
https://maxroll.gg/d2/d2planner/c5ad30ytOr if you want to go with the popular slower approach, replace merc with defiance, give him infinity, summon IG with insight, max CE. The gear on nec is the same.
You'll need to telestomp mobs to try to get your merc to kill one of the mobs that are dying from your psn nova, just to try to get a corpse and kill the rest of this one pack faster instead of killing multiple packs simultaneously.
It'll take more time to lvl up, but some people really don't want to move on if the mobs on their screen aren't dead yet.
D2:R