Chayula whirling assault - looking for ways to improve further (mostly tree-wise)

Hmm, aside from body armour and helmet upgrades, I at least don't see much of an issue with survivability. If you're talking about big hits, a bigger pool would solve that issue, but that means getting into a 1100 body armour or 600 helmet, etc. If you're having issues with getting stunned/ailment, you may need to invest a few nodes into stun/ailment threshold, since you're pure es.

The only thing I can think of is running a high end evasion/energy shield set up, that can usually up your ehp to 40k if invested enough. You'll be at a ~6-7k energy shield, but will have at least 70% evasion. Damage can vary depending on what nodes you take.

However, that's just my experience with invoker monk, not sure about chonk.

Running essentia is very nice for the life leech, but if your clear is fine, you can think about dropping HH for soul tether with the conversion. Run +2 melee gloves with some high energy shield rolls for more defensive while keeping damage.

Put all your remnant passives in weapon set 2 (and arguably take more of them if not all of them), as long as you enter an area with your weapon set 2, you'll retain all those passives even in weapon set 1. Use whatever points you gain from that to increase either offense or defense on weapon set 1. You can put more of your damaging passives directly inside the weapon set 1 to use it more effectively.