The article mentions that even standalone apps can update themselves without user permission if they follow the requirements, Epic Games Launcher/Store is also a standalone app that needs to update itself at some point.
It doesn't change the initial installation dance with allowing "unknown sources" with all it's "scary" language and hoops a user has to jump through it seems; maybe that's what you meant? At least for Epic this will still be a problem as they see this as a clear disadvantage: https://www.theverge.com/2020/4/21/21229943/epic-games-fortn...
I'm not 100% sure, but I think you're incorrect about this.
From TFA:
> However, user action won’t be required for an app install/update if all of the following conditions are met:
> ...
> The installer is either updating *itself* or installing an update to an app it first installed.
Emphasis added by me. If you request the new permission, target Android 10+, and update yourself, the user shouldn't be subsequently prompted.
(If my reading is correct.)