Very impressed by what you've come up with - it will be brilliant not to be worrying about failed paste!
I see the liquid metal pad is now in the store. How easy will replacement be if that's needed?
https://frame.work/gb/en/products/16-liquid-thermal-pad-amd-...
We're writing a step by step replacement guide with videos, but it is pretty straightforward. You let the system cool, remove the heatsink, take off the solidified liquid metal pad using a sticker, apply the new liquid metal pad that comes attached on an alignment film, and reassemble. There is then a burn-in process to ensure the pad melts into place.