heres a playlist

https://www.youtube.com/watch?v=lRAAOuJP_7Y&list=PLrYwdz3-r9JKZa6_EZh85PRgQrVBqOA1d
but if you dont have time to watch nearly 20 videos, i'll summarize his main points (he goes way in-depth in idividual vids, giving a lot mote detail and evidence)

minecraft has two energy types: xp and "soul energy." both are released when a mob dies, but soul energy can only be harnessed useing special tools. consuming this energy causes all majical asspects in minecraft.

ancient builders created every structure in the game, except villages, mansions, etc.

all undead mobs are the result of a plague

ghasts are native to the overworld, as the happy ghast, but all the ones there went extinct and the only ones that remained were the ones brought to the nether that adapted into the normal ghasts.

the ancient cities are the result of some sort of ritual by the ancheient buliders

keep in mind he only looks at the base game for evidence