The YouTube Shorts functionality of YouTube (which is a pernicious addiction machine) won't function unless you have Watch History turned on. This is true both for Mobile and Desktop.
So just turn it off, and suddenly Shorts is gone. Good riddance.
On Desktop I use a Chrome extension to block YouTube recommendations & homepage, so turning off Watch History is not a big deal. I just access videos from the Subscription tab.
From my perspective, the only downside to turning off Watch History is that if you re-visit a long video you were partway through watching, then YouTube won't resume from the timestamp where you left off. It will start from the beginning. This has the side-effect of making me unlikely to watch long videos, which is probably a good thing.
There's also this Chrome extension for Desktop which will change the UI for Shorts to match ordinary videos, and also redirect URLs to try and thwart the scrolling feed functionality. Unfortunately, I am too weak willed for this to be effective, I just press the Shorts button over and over like a gambler, despite the redirects.