Sorry OP, just... git gud.
And learn to play this game. You seem to not understand it at all. Get your armors and elemental resists. Get higher initiative FFS.
And if the devs decide to rebalance the unforgiving gameplay to being just another grind-fest with zero competition - do it only for explorer difficulty, for all the crybabies to play in their little ponyland, please.

P.S. On my first ever D:OS1 playthrough my party wasn't nearly wiped by that Braccus' meteor, though it was kinda unexpected. I did win it only on my second try, cause eventually I still got mowed down with the twins and ghoul, but still, the meteor wasn't a total disaster. So just git gud.