[Andrex]

> it won't make things easier for "standalone" third-party apps that only update themselves, since they will continue to be marked as originally installed by a browser or file manager app

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.)