Would help to see your ship fit. Also what your piloting tactic is…
Anyway, best to take out the Sentry’s first, then work on the NPC’s. That will cut out quite a bit of incoming damage. I believe each NPC group spawns with destruction of last NPC in previous group so don’t kill the last NPC in initial group until you’ve destroyed the Sentry’s.
Personally I think a brawler fit for up close combat is best.