Bitcoin goes up, the flows into ETFs are up

Which comes first?

The flows into the ETFs and then bitcoin's price, or the price of bitcoin is up and then money flows into the ETFs?

Intuitively one would think that the price is up after the flows into the ETFs.

However, it seems to be that when the price is up more money flows into the ETFs.

(Source: https://twitter.com/HODL15Capital/status/1777434524961431604/photo/1)

Price of bitcoin is up, people buy the ETFs.

Then it goes up even more, self fulfilling.