It doesn’t take much to refute this claim. If iOS browser is so much worse than Android’s, why don’t companies just make an iOS app and tell Android users to use the web app?
Also, it came out in the Epic Trial that 80% of App Store revenue comes from pay to win games.
Outside of games, the most popular apps either front services that don’t have in app purchases at all like Spotify, Netflix, Facebook etc.
Though one could say they deprioritize their own browser in order to push producers to using their more lucrative app store.