Because of the way youtube serves shorts the exact same way it serves any other video it sounds like a man-in-the-middle proxy server would be needed. which to enforce would still require per device config(loading corp style keys). A per device config that would probably be trickier than a shorts killer browser extension.

This is why DoH makes me nervous. Once the embedded ad engines(cough smart tv's) figure it out, we will no longer be able to mitm our dns services. Or to put it more plainly pi-hole will stop working. An open question, Any good way to block DoH? Or are heuristics the only answer?

An unenforceable option would be to set up an independent youtube frontend. https://invidious.io/

My opinion on shorts is a little more generous, sure they are generally brain-cell destroying bottom of the barrel clickbait nonsense. But that can also be said about most of the rest of youtube. What I hate specifically is the shorts doom-scrolling interface. It turns out a "short" can still be viewed on the normal interface. So I use a browser extension to turn shorts urls into normal urls.

You would have to break E2E encryption, no? I think, at the very least you still would have to manage new TLS certificates per device to MITM yourself. I mean, doable, but also kinda nasty.