Extreme CPU usage when many monsters spawn, dynamic culling/resolution do not work

Bug Report ID: #636,294,831

The game lags extremely in certain situations, and it seems to be tied to the spawning of monsters. I notice it when interacting with legion, harbingers, and beyond, though it might also happen with similar mechanics that I haven't invested in much this league. When this happens, my displayed cpu delay jumps from 15-20 ms to about 300-800 almost instantly, and my frames drop to 1-2 fps, which is probably still exaggerated by the performance graphs. Then, my inputs are only registered with a delay and I have to exit to login screen or die. Notably, dynamic culling and resolution both do not seem to affect the issue, as nothing changes when when I disable them or change the target framerate. Dynamic culling does, however, work in poe2, which runs relatively smoothly with it enabled and never strained my cpu in any way.

My specs should be enough for this game, and my system monitor also does not display the cpu usage indicated by the 300ms delay.
While I am playing on Linux via Proton, this has worked perfectly for me in the past, and just last patch in poe2 as well.

In-Game Setting: everything on the lowest graphic setting, although it does not affect this issue. I am using Vulcan. Dynamic culling is enabled with a target framerate of 15. Multithreading is enabled (and all of my cpu cores are equally in use while playing).

PC specs:
CPU: AMD Ryzen 7 5800X3D 8-Core Processor
GPU: Radeon RX 7600XT
RAM: 16GB

Here is a screenshot of when the problem occurs:


It is not very helpful as you can't see what is going on. I did also record a video, although I am unsure how to post it here.