They're 60, I'm 75 with max gear... guess I need a lower toon then

I'm an experienced player trying to play through the kotfe story with a new player who recently created a boosted toon just to experience the kotfe story. They bring me over into their story instance, however, I seem to be the only one capable of doing any damage at all. They swing and swing dealing no damage whatsoever... while I tear through everything like butter. Any ideas about how to fix this? We've tried logging out and logging back in. It seems to fix the issue for one fight. I try leaving and coming back in, it seems to fix the issue for one fight before that doesn't work anymore.

Help me with this. So I pop onto a veteran flashpoint for the first time in years... I'll admit that maybe I've forgotten how things work. Get onto Hammer Station with a group of pubs. I'm tank. DPS person runs ahead, agros TWO groups of enemies by shooting at them from around a corner. I jump in to take all agro off of the DPS (my job as tank, if I remember), and DPS, without saying anything, runs ahead and leaves me and one other DPS to fight them alone. Everyone dies. Then they call me an idiot for attacking two groups of enemies, and start running ahead without telling us a dang thing about what they're really doing. Then he says we don't really know how to run a flashpoint. So... is there something I'm missing? Was he just trying to speed run it or something? If so... shouldn't he either explain what he's doing first since he's with a bunch of random people with varying degrees of experience or save that kind of thing with a group of his friends or something? I mean, I'm fine speedrunning, I suppose, but is it automatically assumed when you start these days that it WILL be a speedrun?

I have tried resetting the quest multiple times, but I can't get past these seemingly bugged doors