My phone is running iOS 14 still and it never got those super annoying pop ups that previous versions of iOS used to push out nagging to upgrade.
I only have a red dot on the Settings app which is fine.
No nagging pop ups randomly blocking the screen a few times a day pestering me to upgrade.
I used to use the TVOS beta profile on my iOS 9 iPhone but I’ve heard that that method no longer works. Don’t know.
Don’t need it if the pop ups are gone for good.