It is part of the deep web, just like Discord or any sites hosted on private companies intranets. Lemmy is not, you can just hit any instance with a web browser and view stuff.
To be completely clear, dark web/net and deep web are two different things. That wiki link you used is describing dark web stuff like tor etc.
Absolutely filthy prodigy remix in the first video. Gotta love the russian at 1:15 looking like he’s trying to get a rewind for that drop but really just can’t move his leg or floppy foot lol.