I may liquid metal my gpu aswell. Mine is lower class though - 6700xt. I've had pretty bad hotspot temps since I installed my blockbuster nothing stupid. 30C more than core temp but never higher than the 80Cs so haven't bothered. Just need to make some room to sort it out.
EDIT - if it goes wrong that's my upgrade excuse
The only time it will go wrong is if you spray the stuff all over the pcb. Liquid metal can be unusually resistive to coming out of the syringe, that's the danger moment (that and over application) so try applying to a bit of cardboard first to get an idea of how quickly it comes out.