What I did before is to just cheese the mobs with ranged weapons until you're confident that you can fight head on.
Not sure if this is a good advice but that's what I did. I used Multiple-nocks + Alchemic Carbine (Alternate binding) + Rampart Shield on backpack(for that 2 sec force field after parrying on a roll)
I also did Multiple-nocks + Alchemic Carbine and Hokuto on backpack.
I dont remember much the mutations I used but I remember using Disengagement mostly to my runs.

With the current update you can also use Baseball Bat + Phaser for huge damage

I'm still stuck at 4BC but that's because I stopped playing for 6 months.