In season past, yes it was a one-shot kill fest, however not since last season.
She gives you a debuff that if you get hit enough times, yes it then becomes a one shot.
At least now her attacks give you a clear idea of where and when they will happen. So you can avoid most of them.
You have to learn her mechanics so you can avoid most of those attacks. its a bit of a pain, but it can be learned. Speed helps sooo much with this, because you can out run most of them.
If you have the DPS, then i suggest boost your speed to near max. run the fight a bunch of times and pay attention to the attacks in all the stages.
It can be done. much easier than in the first few seasons.
Keep at it, you can do it.