Primordial Blocks unplayable lag, possibly map modifiers combination (perfect storm)?

I have run into some insanely unplayable lag with this map. The ones before it, fine. Running around in Act 10, fine. It only starts getting terrible when Kitava's cultists start attacking. If they're running or dead, it doesn't seem to be an issue. I am running on lower settings from trading earlier, this is not hardware lag (can play on maximum settings at 60fps @ 4k). I have linked two example videos below. After re-entering the map, it's back to horrible again.

== Map ==
Primordial Blocks

== Mods ==
* Monsters fire 2 Additional Projectiles
* Monsters gain a Power Charge on Hit
* Monsters Hinder on Hit with Spells
* Area is inhabited by Cultists of Kitava
* 63% increased Quantity of Items found in this Area
* 34% increased Rarity of Items found in this Area
* 22% increased Pack size

== Proof of Issues ==
Running the map: https://youtu.be/4azlhR2RgKc (2023-03-02 21-31-12)
Running around Act 10: https://youtu.be/WBXhCrnk73I (2023-03-02 21-35-03)

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UPDATE: I did the Expedition encounter, far away from Kitava's cultists, performed beautifully. Got back near Kitava's cultists and it's struggling again. :(

UPDATE #2: All new maps are hideous until I leave the map, enter any random area, then come back in the map.