Requiring tracking cookies to be enabled before allowing users to see ADVERTISING is a STUPID RULE.
Fewer views, due to stupid rules, or technical problems, will have the effect of REDUCING SALES. Let me explain this in simple terms: The videos on Unity's store are there to PROMOTE SALES. The only thing I can think of is that they're seeking consent for something Youtube assumes consent for, and thus blocking the video until you've said it's allowed. I had to enable that, and I had to 'enable' targeting cookies-though, again, I'm blocking all cookies. You can see that I have every cookie disabled (I've also disabled those for Unity itself), but the video is clearly playing.
I see no reason for Unity to be blocking video access based on geolocation and other cookies. The only thing I can think of is the whole 'this video is not available in your country' thing, but that happens on Youtube's end. If you look near the bottom there's a whole buncha stuff saying 'blocked-video'. I looked at the page source for instances of 'onetrust.' Found this link. I went to a random other blog and found the same behavior. The only links at the top of the page that don't have that source are 'Get Unity,' 'Asset Store,' the forums, and Answers.