Any tips for fighting Geonor as witch?

[chaotic fried rice]

I breezed thru most of act 1 relatively easily without much hassle but now I'm getting skill checked hard by Geonor bro is totally whooping my ass

I was wondering if anyone has got any specific tips to make my character better I'm playing as Witch & my build rn is focused on using minions like skeletal warriors & the bone spider things from unearth & chaos dmg so i'm using chaos bolt & contagion a lot, but also some others like elemental spells just to experiment with: flame wall, ember fusillade, sparks & the electricity orb thing

I'm thinking I might portal back to town & try equipping some different better skill gems I got in my stash & try to specialise it more, cause maybe my skills are not good enough or too all over the place or maybe i just need more hp & defense it feels like my character is a bit too squishy

[ughhhhh]

every time i fight this boss i optimise for cold resistance. the rest of his moves do large physical dmg, just be more cautious of those.

[Platzetta]

I think last time I nuked him down using SRS (Summon Raging Spirits), flame walls, Skeletal Arsonists, Flammability, some skeletal warriors that I sacrificed with Pain Offering to buff up the arsonists and stuff like that, combined with passive nodes to boost up minion damage, survivability, attack speed etc. Stuff like that, but it's been a long time since I've done that boss while leveling a character.

Also wearing that cold res charm for extra beefiness for his ice attacks.

Figure out all the support gems to beef up your skills and also upgrade everything you can.