As a developer myself, I respect and understand that it's not their fault that profiles are useless

As a consumer, I don't care whose fault it is that profiles are useless.

the developer needs to write code to detect the current profile. Most app’s don’t do this, and they explicitly ask a 2nd time. Not apple’s fault.

There are some apps that get this right. Infuse recently added support for this.

I don’t know I think Apple should be able to keep COW filesystems for every user to apply atop a read only file system. Unique apps, unique settings (maybe unify tv settings into admin panel) and no cross-contamination or need for app owners to switch profiles. macOS software doesn’t need explicit understanding of profile switching, neither should iPadOS software.

It's not the end user's problem whose fault it is.

as an end user it is my problem when trying to complain in the right place

I agree with you.

and the end user can blame Netflix, Prime Video, Disney+, YouTube, etc for not delivering the best experience for their customers. ¯\_(ツ)_/¯

Or they can blame Apple for delivering a developer experience to those companies that makes those companies not want to play ball.

Not that they likely will, as Apple owns the framing.