Im not sure why but in the menu the game maxes out my GPU - 100% all the time.

In game it's like 60-70% maybe less.

GPU - GTX 1070
drivers - I believe they're the earlier August 2018 ones really weird anyways.

Enable VSync or set a frame limit from the game's graphics options. I use 120 limit.

I don't see the reason for burning your GPU for nothing at the Menu like this. My laptop suffering from overheating if I leave it with the game running at the Menu.
Also I don't know why, but (same as was mentioned by topic-starter) usually my GPU less loaded while spectate in the game than sitting in the Menu.