Unfortunately, this seems like a problem where nobody has come up with a good solution. Google allows other app stores on their phones and they allow sideloading, which might seem like the ideal situation. The biggest issue then is that Google still has the monopoly on apps on Android because the size of the Play Store far eclipses every other store. So if Google bans an account or app unfairly, the only realistic option is to appeal and cave in whatever they want you to do. Because being relegated to an app store that nobody uses is essentially a death sentence for that app and its revenue.
How do you fix something like that? The power or the problem doesn't go away because there is choice. I feel like Google has neatly sidestepped the problem from their perspective and thus aren't being scrutinized, despite being in nearly the exact same situation as Apple.
A slightly different example. Internet Explorer essentially dominated the browser space for nearly forever until Chrome. There are any number of reasons, but the most obvious is that Microsoft could leverage their position as the platform owner to promote IE over all alternatives. EU tried to regulate it by forcing them to add a "browser choice" dialog, which didn't work. The only reason why Chrome became so popular was because Google did exactly the same thing as Microsoft. They could leverage their search engine, which by that time already owned 90% of the search engine market, to aggressively promote Chrome at every single opportunity.
There are all these examples of tech companies leveraging an existing platform to edge out competitors in clearly anti-competitive ways, and modern laws simply aren't up to the task of ensuring a fair, competitive market where massive companies like Google, Apple, Microsoft, Facebook, Amazon can't abuse their power.
In the same way the government forced Microsoft to de-couple Internet Explorer from Windows.