Google says that Android sideloading "is not going away" in new FAQ

android-developers.googleblog.com

7 pointstimpera3 comments

They just change the rules completely. As soon as my first manually installed app stops working, I am forever done with android.

However, they still plan to make verification mandatory to distribute APKs.

Indeed so.

Fortunately, at least GrapheneOS says this is a problem that's limited to Google Play.