The TLDR version of a different strat, is to keep spending your points on mutations so that the science can never develop a cure. It is possible to go for a really lethal virus right off the bat, and just keep adding new things to it. There’s a trade off in the game for speed vs coverage vs detection. If you have something that’s going to get detected right away, it needs to be really hardcore etc.
The thing that usually catches me out on games where I try to go lethal early, is the lack of the virus spreading to …usually one place. I’ve lost a ton of games because I had 99% or so of the population wiped out, but one area just never got infected.