Well... there is your problem... You have to delid the cpu, and swap out the stock crappy thermal paste that intel uses. I to had really high temps on my 7700k and that is why I delided the cpu. Leaving stock thermal grease between the cpu die and heatspreader while using liquid metal between the heatspreader and waterblock makes no sence.
Delid the cpu and put liquid metal on the cpu die for better heat transfer to the heatspreader. Then use normal paste (that is what I am using) between the heatspreader and the waterblock.
Free tip:
If you delid and swap the stock TIM with liquid metal. There is almost no thermal gain to also run liquid metal between the heatspread and waterblock over lets say KRYONAUT (thats what I am using.)
Maybe...