I feel like this is where the lines are getting blurred and people are getting different concepts conflated.  Anything to do with ETFs isn't "Bitcoin regulation" in my mind.  It's fiat regulation because all these institutional investors would be trading IOUs rather than actual bitcoins.  The actual bitcoins at the centre of an ETF aren't being traded.  They're merely a commodity being speculated upon.

They need permission from their regulators to place bets on our entirely separate economy.  So people mistakenly see these entities as our regulators too.  But they aren't.  It isn't money "coming into Bitcoin".  It's money being bet on the sidelines.  Their regulations don't directly impact us.

A loose analogy would be sports betting.  Gamblers are (generally) regulated when they bet on sporting events.  But the regulators governing that activity are entirely unrelated to the governing bodies of the sports themselves.  By the same token, Bitcoin governance is not dictated by the regulatory entities that govern ETFs.