I see many accounts reporting the inflow and outflow amounts of Bitcoin ETFs.

Actually, it doesn't matter much. Just because many are entering the ETF doesn't mean the price will go up. If many are exiting, it doesn't necessarily mean it will go down.
Institutions don't operate on straightforward logic. For example, some hedge their positions. You might see them buying, but in reality, they might be shorting to hedge themselves. There are all sorts of strategies.