Screen burn iPhone 13

I recently bought iPhone 13 a month ago, when exposed to sunlight specially on a white background, It shows marks all over the screen as blocks as the photo attached.

The phone is still in warranty, when sent to the apple service provider, they said they sent to apple to send another screen for replacement "they'll only replace the screen", and not replace the whole phone. and that it'll take up to 8 weeks.

Shouldn't the phone be replaced completely instead as they verified it's a manufacture issue?

Thanks