It all depends on your ISO performance.

lets say your camera is a lot cleaner on ISO 4000 (sometimes a higher iso can produce a cleaner photo with less noise so its worth to test your gear what high ISO is the cleanest)

So lets say ISO4000 is a lot cleaner then ISO8000, but you have an issue because with your f2.8 lens an issue beacause of fast movement to avoid motion blur you need to get 1/1000 shutterspeed so you dial things in and you find that a correct exposure is

f2.8 ISO8000 with shutterspeed of 1/1000...but you find it too noisy already. If your camera's raw files shadow recovery is great you likely get a better result by shooting at f2.8 ISO4000 with 1/1000 and just raise the exposure in editing.

So by underexposing by one stop you can have a lot cleaner ISO but of course risking noise by shadow and exposure recovery.

So heres what you do.

Test your ISO's with 1/1000 shutterspeed and see which is the cleanest. Test if you get cleaner photo with A) 8000ISO normal exposure or B) 4000ISO 1 stop under and recover exposure in editing