I am struggling to get my arms round this I mean, it's not actually about the browser, but let's ignore that. Companies that sell phones choose to install a particular OS. Apple's choice is obvious, for others (99.9%) it's a version of Android. The vast majority of those choose to use Google's ecosystem with its Playstore. Much as I can understand the sentiment, I can't see how it equates to a stranglehold. If others…
Regarding the app stores, it seems like lawmakers are catching up with the idea of "If I buy it, I should be able to own it and make my own decisions", which includes being able to install applications from 3rd party developers. It seems like a fine idea that Apple has a default application index where you can install applications from, but what is not fine is Apple deciding which application indexes should be allowed to exists in the first place.
Kind of like how lawmakers wouldn't look the other way if suddenly all macOS computers only allowed installation of software from the App Store. Purchasing a device shouldn't mean "The company decides what I'm allowed to install on this thing".