I have a way to make the exynos 990 perform similar to the snap variant.
My exynos 990 performs really good barely gets even warm.
This is how i did it:
Ps you need google translate.
You are basically compromising on all the device features, however there is no other choice to try to limit the 990 problems apart from what you told to do
If we had the snap 865 we wouldent need compromises, however i dont really feel as im compromising things and i get around 50 to 55hours on a single charge so not too bad considering.