VaM is a very demanding game. It is a beauty of an performance-eating monster. Especially in VR it is one of the most demanding ones, I have seen so far.
It lacks some badly needed hardware optimization, and therfore a brand new version is in creation for some time and will hopefully be published sometimes in the future.
There are many things you can do wrong in VaM: using multiple light sources will eat up rendering performance, badly optimized clothings with too many polygones, hair styles with too many segments will torture your PC with severe physics calculations aso. This is something you should avoid if possible.
No offense, but your 1070 isn't the optimal GPU for VaM anymore and somewhat on the "minimum requirements" side.
I don't know If you are talking about VR or flat desktop mode, but In VR even in the starting scene there is a low, but constant rendering workload going on, that you won't have in pancake-games.
Even in the main menu VaM is showing a simple, but somewhat demanding scene with some high poly 3D meshes and textures, being constantly rendered in realtime, may it VR or 2D. This might be even more than in some well optimized AAA games with usually low poly meshes and low resolution textures.
I don't know your GPU... are those 80C normal temperature or hotspot temperatures?
For a hotspot temperature 80C is pretty normal at demanding VaM scenes. For a base temperature it is somewhat high. VRAM modules can stand a hotspot temperature of ca 100C and a bit more. But you most likely won't reach this temperature, because the GPU is automatically throttling down long before this.
As Keycode said: There are many different things that can negatively influence heat in your PC case.
As VaM is very demanding: Maybe you have to drop some GPU OC settings and enhance the speed of all your case fans up to a point that is annoyingly loud, to cool down your poor 1070. Maybe try to open your PC case for testing if you have insufficient airflow, aso. This was something I had to learn when I still had my old 980ti which should be somewhat similar to your GPU.