If the goal is to get 100million downloads, what would be the best way to do that??
100M is a lot of downloads... (literally 100000000)
I was very happy when my first game got to 100 downloads, and now I'm chuffed to see my third game get to 300 downloads with no advertisements for it =D
I guess if you want to take the "high way" to a lot of downloads, make something YouTuber friendly (horror games and silly games do really well for their channels)
Also don't reach out to big YouTubers... Even tough one of their videos on your game could help you a ton, they will probably never check your game because it will not be as "hot" like a new AAA horror game...
Search for some smaller indie showcase channels and work your way up!
I myself prefer to be more like the typical "I'm an artist, you just don't understand my work" cliche, but if you prefer the "high way" route, go for it!
Best of luck with reaching your goal!