I ended up watching it, and I thought it was generally just okay. Basically, here's the tldr from what I remember:

1. Doom was originally a "virtual reality adventure" game - I guess that was the terminology for "first person" game back in the early 90s
2. Doom clone became a thing for a couple years until Quake came along, at which point "Quake killer" was the term used; just prior to this, "first person shoot'em up" was used
3. Some random discussion about what Doom would've been called if it didn't get popular - not sure what that speculation is worth imo, maybe trying to discard biases?
4. conclusion that Doom was actually an action RPG? Because it has similar gameplay as gauntlet? Gauntlet was a hack and slash dungeon crawler, not an action RPG, so the proper conclusion imo is "first person shoot'em up dungeon crawler," the "action RPG" argument came out of left field

So that's my take. I don't think it was a particularly noteworthy watch, and I'm not particularly motivated to subscribe to watch more. It was okay though, so I'm not going to avoid the channel or anything.