trying to make the poisonous concoction build better

https://www.pathofexile.com/account/view-profile/creatia835/characters

path of building https://pastebin.com/VbWxywLw

TheExGf is my charter and I'm kind of lost on how to make her wither clear faster or get tankier. apologies if my spelling is horrible in this poast. any help/ recommendations would be lovely. i find when i do get hit i lose a solid chunk of my health i love to delve and run simulacrums or delirium but i find killing the tankier enemy's slow for example kosis i belie his name is for delirium bosses takes a min or 2 to kill him and that's when i find him on a t16 map alch and go style im wondering what kind of armor i can craft/ buy on poe trade that would be better then mine only have about 3 divine worth of currency however but i can farm more out just might take a min. for example i know running the chance of corrupting my unique chest to get plus 2lvl socketed aoe gems would help. would crafting a better amulet help more or getting better jewel's for the skill tree help?

Here's my character from 3.17 (the last time I played one) in case it helps you:

https://pobb.in/PO_dalgKGB4B

Some general tips:

1) If you want a lot of damage, you need to go with 2 large cluster sets. The reason is that poison does not have a lot of nodes for damage from just the tree alone.

2) If you are a Pathfinder, you generally want to set up so your pots are always on (standing in hideout, not just while you are killing because that falls off if you fight a boss), since it's not very hard to do so. Rolling for either Chemist's or Perpetual plus minimal other investment other than ascendancy is all you need for that. PoB says you have less than 40% pot uptime standing in hideout (notice in mine, it's 100%). Especially with defensive pots because when you die, it's generally because your pots are down.

3) Witchfire Brew is a waste of a pot slot. Dump it and get a despair on hit ring if you need despair.

4) You need to roll a better life flask because much of your damage comes from this. Saturated Divine Life Flask and make sure it's 70% if possible (I'd buy one if you don't want to roll it). Once you have that, run betrayal and get it max qualitied on the Hillock bench.

5) Divergent Poison Concoct is expensive but totally worth it because it allows you to ditch the wither totem setup. On my setup, I have 46% chance to wither on hit basically, which with how fast and how many I'm throwing, guarantees bosses will be on 15 wither stacks.

6) My character is flawed in that I didn't go Spell Suppress. I'm glad to see you have suppress. Work to get that to 100%, then ditch the point from Versatile Combatant so that you can keep your 75 block. The reason you want this is, if you look at my shield, there is a Crusader mod that gives 1% inc damage per % chance to block attacks. This works for poison and is a massive damage increase. Does your shield have an open prefix (can't tell for sure)? If so, you can get this mod by slamming a Crusader Orb on it (100% chance because that's the only crusader prefix on shields).

7) Your jewels are trash. Projectile damage, Attack Damage, and Area Damage do not work for poison. They do nothing. So you basically have 2 jewels that each only give the 6% life, which is a waste of a whole jewel socket for.