I use the following traits:
-Card upgrades level 8
-Starting level 5 or 6
-Starting health level 5
Health per level rank 4
Regeneration any level ( it doesn't matter for story boss fights tbh)
Here are some relics where I think you need to have to stand a chance:
-Amulet of simplicity because it makes the basic blocks pretty good -Guardian Totem is an ok way to start, but you might beat her without it too -Aconitum+ring of the snake= gets rid of any totem buff
-Fertilizer is pretty decent too because it halves the damage
-Pro sunglasses are good with living root
-Phantom shell is not bad to start the fight, but you don't really need it.
For tips, I'd say to have a lot of poision, defense and quake/fission moves so you can deal constant damage, but be sure to have some powerful damage moves too. In rest, it's all RNG