Arelith

Could we try removing those in Avernus/Benwick ? Prompting this, since it's not the first time that I die there because, well, I can't do anything due to that awful lag. I don't think those bring much to the area or immersion.
Same goes for the Arcane Tower, I think it has been asked many many times. Also people were quite happy with how it was when @Spyre removed them one by one to fix a bug, and it stayed like that some time.

For clarification, do we know for sure that it's surely the number of VFX that causes the lag, or are there a few specific VFX that cause significantly more lag than the others? The quantity is obviously a factor, but removal of a few key lag-producers might be an effective solution.

Spyre may know, since he took them off the Tower one by one, I believe.

The VFX within Benwick that basically tanks everyone are the tentacles. It's the only reoccurring feature.