At first Google does plan to offer something called “advanced flow” that will let you install what you want. But this doesn’t address the chilling effect for developers (some are just getting out of Android rather than registering and paying Google), or the censorship power it hands to Google to make “undesirable” apps harder to obtain and install. And there’s no guarantee they won’t just withdraw “advanced flow” one day.

https://developer.android.com//developer-verification/guides/faq#advanced-flow

The best way to avoid it is by installing an OS that doesn’t include the developer verification component.