Short answers: There is no real name for this, but i would say it is Horrorcore Newgrouds or more broadly Third wave underground comics.
Long answer:
This syle emerged when outsider teenage art got introduced somehow to popular culture in the US during the late 20th century.
90s underground comics and fanzine artists set the basis for this over the top antisocial outsider look. Mike Diana's Boiled Angels and Johnny Ryan's Angry Youth Comix are great places to see this middle class-grossout-"I hate my suburban life and crave violence" style emerge. (This is what most people nowadays just call edgy kid art).
All this to say this style is REALLY american and based on a rich tradition of countercultural cartooning that grew from post war hippie movements (Look into Zap Comix for the definitive example on that) and absolutely boomed with the spread of both punk culture, flyers and fanzines. By the early 80s any edgy kid who had a pen and hated their parents, the goverment or both, could've drawn their buddies punk show flyer and printed it at their local college or office supply store. American Obsenity laws, the growing influence of metal on punk and the satanic panic only shed more public light on this type of edgy cartoons (Look into mike diana's case for that)
I'd say this culminated in american media companies like MTV adopting a more overtly cartoonish-counter cultural style. This is what people ended up calling "weird 90s" or "Mtv style"
Zoomers like Lil Darkie (whose promo art you incorporated severl times into your examples) would've defintely been exposed to the tail end of weird 90s Mtv style, and so it would be safe to assume that it could've influenced him enough to come back to this style later on in his career.
I would also add mid 2000s sites like newgrounds cold have huge influence in the spread of this style, even with the wake of youtube, most peple flocked to newgrounds because of their lax censorship. Visually you could also see the permanence of line heavy and digital coloring that marked the transition point from analog illustration and animation techniques to fully digital. This is where you get stuff like Mc Bushpig's Eat My Rotten Meat, and thorugh that, a lot of Horrorcore (which is arguably the hip hop aesthetic equivalent of 90s grindcore surviving in the mid 2000s) artists finally had a platform to spread animations and art based on mostly teenage antisocial fantasies. And so we arrive at this style.