If you had to show someone a video on YouTube that gave them an explanation of what D&D is, and how it's generally played (rpgs in general), which would you choose? Preferably with at least part of it being actual play.
I thought Mike Mearl's Tower of the Curator was a decent example. It's not a full 4 hour session, just an hour and a half, so a little bit easier to digest. Eight entertaining players who display a variety of play styles. High production value, but not overly dramatized. DM thinking on his feet and player hijinx. Plenty of humor. Pretty tight dungeon experience covering all three pillars.
Runesmith and DavvyChappy both probably have something like this. Both of them produce videos around the 10 minute mark for length. Might not be comprehensive, but certainly more digestible than a Critical Role stream.