Starter maps mercenaries feedback

Ok so I decided to give the league a try and lvled a fresh RF chieftain.
Apparently, it's not the best build to go vs mercs cause even in strater gear in t1-t2 maps it gets 1-shot constantly by any merc while I currently have 4k life 1k regen and 84/81/81 res with chaos lacking but that's not the point cause I tried different dmg types mercs.
It's cool to see them being powerful, but should they really be that hard to kill considering map bosses in same maps give me zero trouble? or should I gear up for pvp to be able to actually tame one of the map mercs?
I mean I know my gear currently sucks and all that, it's just a bit of a feedback on the balance of the whole thing from a perspective of a fresh character starting endgame gear and pointing out the power difference in the mercs power vs everything else in the same map they're standing in.
That said, the last merc that I had from lvling from like act 7 is still doing well in same maps while being quite underleveled for them but still not getting even close to dying in many situations. So kinda looks like they are a bit overtuned.