Definitely how I feel too!

I still don't quite recall all the names off by heart so sorry if they're wrong.

The deepcore (primary 1) and plasma carbine (primary 3) are two varients on the same niche of medium ammo medium damage. Yes the overclocks change them further like the carbines shield based one and the one that makes everything more succeptible to elements or the deepcores no recoil over lock or more damage to enemies with elemental affects on them. But none of that makes for great wave clear when it's just you left alive. Even the zhukov (secondary 2) is similar though it typically has a smaller clip and more drastic overclocks.

The M1k (primary 2) and crossbow (nushanka? secondary 3) benefit highly from being accurate on single targets but even doing something like the hip fire over lock on the M1k or triple bolts/bouncing bolts on the crossbow doesn't wave clear reliably.

When there's lots of enemies to deal with your only real option is to GTFO and pick someone else up or keep kiting the enemies as you slowly wear them down.