Honestly I have done all I could to stop eevee from stopping the flickering on my volumetrics. I looked up every post in this Forum, and none of the suggestions help. No matter , what I do the volumetrics, just flickers at like 1 second intervals. There is no animation this is just a still, without any camera movement, nor with any environmental animation, the fog in volume scatter just keeps flickering. I did the volumetrics clamp thing from 10 000 and going down. I raised the samples, I increased the density, no matter what I do the flickering continues. I am at a loss at the moment, if anyone else has discovered the solution please please share.
I think it is not flickering in your viewport, eevee is calculating the volumetrics in your scene sample by sample.
What is your graphics card and processor you have on your computer?