Can't add much value to the topic but I will just leave it here that I have GD900
'the original edition' on my RX 570 for ~5 months now with no issues.
Its holding about the same temps as whatever Gigabyte put on it in the factory, maybe 1-2 Celsius lower but its hard to tell here cause my room temps are all over the place all the time.
In general I'm using MX 4 for years now on my CPU, it gets the job done but then again I run everything at stock so its to be expected.
Checked now and MX 4 2019 edition and the new MX 5 is pretty much priced at the same in one of the biggest retail shop in my country at around ~7$ for a 4g tube.
In comparison the base Kryonaut 1g is slightly more expensive than that so I don't think I will ever switch from the MX line as it proved itself to me over the years.
'last time I let it on my CPU for 2 years and it wasn't dried out at all'
As for weird thermal paste ideas, well theres a known tech dude in my country who likes to try out really weird stuff.
He tried peach jam, chili sauce and basically anything in the household that was possible to apply on a CPU/GPU and compared them to the MX 4 baseline.