Since Blackrock is a 10 trillion dollar company, they technically are able to manipulate every market in the world.

Yet, you look for the wrong places. I would not worry about ETF price manipulation, since they're highly regulated. I would rather worry about classic crypto exchanges and their fake trading activities - providing fake volume, fake orders, selling the order flow in secret, etc. In an efficient and liquid market, every exchange would provide nearly the same price for bitcoin. What do you think, why are there .5% differences? Exactly.