the chargers are fairly easy to fight with the taser, strafe jump and turn towards them, it has farther reach than youd expect.
The fire spitters are super easy, they show an animation as they go to spit, the moment they do you strafe and avoid it and close the gap to hit with a taser. I killed a large spitter with just the taser this morning in the desert start(decided to do a second playthrough after i maxed tech on my first save)
It takes time to get used to their attack patterns, but they are incredibly easy to fight. Only challenge I've had so far was giant spiders, and only because i had mistakenly had my rebar gun out instead of a taser.
Rebar gun is good for one thing to me, use it to destroy the pods that explode into bugs from a distance far enough that they dont aggro, then you can pick off the bugs and not take any damage. Rebar is also great for picking at enemies outside of aggro range or below you.