No spoilers in here just saying.. This is for if you are having trouble.

When you die you respawn behind this massive shield to stop you
from safe spotting it. Jump up on the rock behind you and you can
shoot it over the blue shield. Took me about 20 minutes to kill
since i have terrible guns but if anybody is having a hard time doing
it alone then give it a shot.

From this spot you can go back and buy ammo without health regenerating.
I suggest an elemental weapon to help with the damage.

Not very clear explanation on where it is but i would be willing to
show anybody where it is.