Low spec pc struggles with 20 mobs in forest maps when using any kind of aoe attacks

Heyo!
I play usually on 5-24 fps thanks to many shadows (please add option to turn of shadows helps a lot in low spec pc/laptops etc) soo the thing is in every forest map like chimera wetlands when i'm surrounded by 20 monsters or around 20 while spaming poison gas arrows and then using toxic growth game screen enters sth ala frozen screen tho i can still watch how from time to time my hp decresses at that time my ms always jumps from 50ms to 450ms and i don't know why even if my connection on pc is still the same(i won't add any screen shots bcs idk how on your page to do that).
To make it clear i already turned everything to the lowest in options and even in config file and i still struggle a lot
Another issue comes when i join other players or other players joins me i usually lose 2-5fps per player and don't know why. Characters like Sorceress that build uses lighting sometimes make my game crash on maps like The Dreadnought (moving from caravan to caravan and fighting monsters) or any kind of forest maps (usually 1-12 fps rarely 3-15fps) same goes for maps like Ogham Manor last boss arena and The Titan Grotto boss arena

That would be all for now i guess

About my laptop
16gb ram
Nivida GeForce GT 740M
Intel core i7-4702MQ Cpu @ 2.20GHz

Tell me if i have to add more information about mine laptop that i use to play the game (and once more please add option to turn off shadows they're one of main issues why i have such a low fps value also maybe sth with water it also affects greatly fps from my experience with games in generall)