Hello, I was searching the official documents, and I found this.

https://developer.android.com/developer-verification/guides/limited-distribution?hl=en

We're committed to keeping Android an open platform for you to learn,
experiment, and build for fun. If you are a developer who doesn't distribute
apps widely, we recognize that your needs may be different from commercial
developers and have provided an account type for you.

What can a limited distribution account do?

1. Register apps
2. Share apps with up to 20 devices that end-users have explicitly authorized.

How much does it cost?

This account is free.

Unfortunately, it still requires government-issued identification.
Yes, the apps distributed via F-droid are not included in this, but I think some discussions are needed, since the project's website says:

This includes apps shared between friends, ... built by hobbyists for personal use.

Thank you for attention.