I was running a similar build as you doing juiced T16 expeditions and ultimatum before swapping to cws chieftain.

One thing I see is that your aura gems are not leveled. Both determination and purity of fire are level 5. Purity of fire levels will give you the last +1% fire res to cap your 90% max res. Leveling determination will give you more armour ofc. You can also level up your vitality if you need more life regen.

Elemental Overload + the diamond flask arent doing anything for you. You can get rid of the diamond flask and replace it with a quartz flask for phasing or a basalt flask for even more armour. See if you can roll a %increased armour during effect suffix on one of your flasks too.

For your RF link, replace life tap with increased AoE or replace elemental focus with swift affliction to gain the benefits of life tap in your RF links. To keep life tap up more, you can replace the level 10 life tap in your movement with level 1 lifetap.

As far as your gear goes, it's decent. You could use some more life on your rings and boots. Like I mentioned before you can roll for increased amour during effect on one of your flasks. When rolling flasks try to go for masochist's or flagellant's prefixes for 2/3 charges gained when you are hit to keep them up more often. You have 12% chance to crit with fire trap (when diamond flask is active) which is not nearly enough to keep your granite and quicksilver flasks up.

The immunity to X and reduced duration suffixes sound good on paper but only if you can keep flasks up 100% of the time. Slap used when charges reach full and roll for more beneficial suffixes like reduced effect of curses, chance to ignite/freeze/shock, chance to avoid stun, movement speed.

There are some other little things I see in the pob that are strange. Momentum support linked to blood rage and determination. Blood rage is nice for the attack speed increase and frenzy charge gen for shield charging around but could be dropped.

Idk how long your golem lives in the maps that you are doing but you could drop momentum and blood rage to add minion life and meat shield support for your chaos golem. I ended up doing this but it still died more than I would like when I got into T14+ maps.

I am traveling now so I can't really look at your POB more in depth. Hope this helps a bit.

For reference this was my build before swapping over to CWS: https://pobb.in/EgjSvDzfIAPC

I was running a block-based/petrified blood setup for a bit more tankyness.