game is too hard

any1 here can please tell me what im doing wrong in dos2, i played the game for about 10hours and it's really hard for me, i see in videos ppl dont have nearly as much trouble with the fights im having trouble with, im at lvl 3 and assassin main, rest of party is knight healer ranger, im getting rekt by camp boss fight and prison key fight, they usually deal way more dmg than i do and idk how to deal with their stuns and other cc, i know to not stand in a group together and tank their aoe but for example, 1 single ice shard puts 2 of my chars below half while i barely dent them with all mine

it's now pretty much impossible for me to progress, like i can't even kill the frogs in the ambush fight in the cave in fort joy, basically the enemies deal way more damage than i can heal/output, the camp boss fight i mentioned, their 2 casters just deletes my chars, what am i even supposed to do(i already try to kill their casters first, but 1 sawtooth from camp boss does like 60%+ of my char's health), then the prison fight, from the melee guy 1 stomp does 50%+ to my entire party, then the rangers finish me off, before i even get a chance to do anything

i know it's supposed to be "hard" but i just dont know how i'm supposed to get better other than maybe starting with a new char with a diff class, i've looted everything i could, i've done pretty much all the quests possible, originally i had trouble with narin and mogi fight too but i'm past that, now the problem is even though i know the mechanics i simply can't match the power of the enemies, not by a long shot most of my chars have 10+ armor/magic armor, but all that means little to nothing when 1 spell does an avg of 15, and 1 enemy gets to cast about 2-3 times in a turn from range, not to count the stun and sleep i receive in between, by the time i even walk up to them to be able to attack, i'm already dead for example in camp boss fight, i start with force attacking some caster on the side to try to finish him off 1st, then before it even dies, i'm getting chained by ice shard/staff of magus/etc. from range, then at least half my party is below half health, and it just worsens from there even if i were to find better eq for more armor/atk, i don't see how i'm supposed to pass that much of a difference in power between me and them