I've been thinking punch-hole for a long time to solve this issue and in a way my move to bigger screens has both made it more of an issue and offers a solution.
My current main screen is a 42" 4k which replaced an assortment of 24" THD screens in horizontal and upright, because there is lots of content that really fits the upright much better. So I find that most of the time I partition it into two upright segments, or perhaps add a horizontal divider on one of the two when things get busy.
Obviously with that size that moves the web-cam very much off my eye focus and while it sits between the 4k and a 24" survivor on top of the 42", it's never quite where I'd look, no matter where I move the conf window.
So for a pure work monitor, having a punch hole camera smack in the middle of that virtual vertical divider, wouldn't really impact productivity, because I only really go full-screen on PDF or documents which themselves have column content. It wouldn't work so great for gaming or movie content, unless they could mature the hidden punchhole camera that is able to display pixels on top (I believe there was a smartphone prototype from China some time back).
Some of my colleages who do tons of confs simply have gone with an extra "social screen", often tablet based, that sits to the side at an angle and shows them in a semi profile, until things get truly personal and they stare right at that smaller screen (and its camera): it gives you the 'power of the stare', yet frees you a bit to multi-task, too.
With desktop real-estate much less of an issue than living real-estate, I think I wouldn't mind a special social screen with a middle punch hole camera, that either stands on the side or can be attached to the main screen. A say 10" extra USB3 connected screen with little processing power behind shouldn't cost more than perhaps €100 and even THD cameras manage to be quite small on smartphones these days.