Note, I am not a heavy phone user and didn’t buy one in years. So my view is limited and I have no idea how the current market is working. So don’t take my replies as “he knows better”, but more like “what he thinks”.

Fdroid can’t be installed by any Android? Its a shop that is installed once like Android store and then it manages and updates all apps from that store. Google is in a similar position like Steam, where the monopoly is only about market share. But the platform is still open.

You also open the phones to potential scammer to have identical looking website and instruct users to install app that steal identity.

Yes, but that is not Googles fault or task. Every shop has to make sure its secure and is outside of Googles responsibility. So this point is completely irrelevant for the discussions about being a monopoly. It’s like saying Steam is responsible for virus and identity theft because someone installed an application on another launcher, just because Steam is seen as a monopoly (I don’t agree Steam being a monopoly, just tried to explain what I mean with context to Android).