Getting filtered as a newbie

[Hebereke]

I'm having some issues dealing with some stuff while leveling.
I'm trying to beat the story missions and I'm currently stuck at 4-2 in episode 1. (normal mode since I can't start gov missions in solo mode).
It's a timed quest on the ruins and I just can't get to the end quick enough.
I'm a HUcast using a buster, giggush and mechgun.
I have no issues dealing with those flying tadpoles and dimenians. No trouble with those centaur like fellas. But death/dark gunners and delsabers? Damn.
One delsaber is easy, just circle around him and beat him. But against 4? I use freeze and confuse traps but sometimes they're just not enough.
Against dark and death gunners it's just a waste of time since they're immune to my attacks most of the time. Is a elemental weapon the answer?
So I can kill them with caution but in this mission I end up running out of time.
I'm kinda lost. Should I farm for better gear or just level a little? I'm lvl 23 iirc

Thanks!

 

[RakeRoberts]

Gunners can be effected by specials on your weapon. At level 23, you could grind hard forest for better gear and level up and have a less stressful environment to work on your mag.

 

[Ryan]

Gunners can be effected by specials on your weapon.

This. Load up Hard Forest, break boxes or kill enemies until you get a Dim or Shadow Handgun, then tekk it up to Shadow/Dark and spam the special attack on Gunners (and Delsabers if you want) until they die to the OHKO.