No fire dancers at all???? sad to hear that. Maybe I live in the cultural capitol / biggest tourist oriented city in Russia, thats why we are spoiled by the abundance of all kinds of creative activity. I see such performances very often. But the photos are rarely successful - the performances usually take place in the evening, to photograph fast-moving objects without a flash - well, you understand.
!BEER
We do get them around festival season, but that's for a single month of the year, during the most dangerous time... for uh, real fires to devastate our environment. :P
For evening performances, you can always just set the ISO to 64,000 or higher, and hope for the best :D I am getting some decent results out of Lightroom's denoise / raw details at high ISOs (Nikon Z6 / Z5 camera bodies).
I think the bulk of these shots were around 32,000 ISO (with noise reduction done in lightroom). It can work, but only just. Noise in the shadows is always a problem!
Ideally, I like to shoot at a low ISO as possible. I have trauma from my firs "bridge" camera, which was a FujiFinePix S SOMETHING (Can't remember the number) - it had horrible noise, no matter the ISO setting.
But it had a manual setting.
It was my last shitty camera before I got a proper DSLR, and since then, its been wide apertures, big sensors, and low ISO as possible. It has taken me 25 years since owning that camera to have faith in any ISO that has four digits :D