Earlier quoted context omitted.
I don't really follow the argument. If you are a commercial company, the Play store is pretty much all that matters in terms of business viability. At a commercial level, the fact a few geeks can side-load apps is next to irrelevant. Who builds a business on side-loaded apps?
The alternative to google play would presumably be the apple app store which, if they ban you, there is no side channel. If your desire is to build a mobile app, you don't really have a lot of options.
It depends on what you mean by "side channel". You can do a PWA instead, or use tools like Test Flight (up to 10,000 users), or leverage the Apple Developer Enterprise Program, etc.