Comment by tmp65535

I have been distributing a pornographic Android app on the web since 2017 and there are no difficulties.

Simply put the APK on a webpage and link to some instructions for installing an untrusted APK. For example, see http://driftwheeler.com

In particular, look at the "Can't install?" link.

If people really want to use your app, they will gladly do a little work to install it.