This writing style is very typical for tumblr girls, they're just now reaching the age where some of them can lead big projects like this. My dear homestuck may not have been a cartoon, but it started it very whacky, and when the author emotionally checked out and hired a bunch of tumblr chicks to finish it for him, it suddenly became very serious relationship drama with some attempts at humor. Looking at Owl House, you can probably expect to see more and more of this in mainstream animation, as severe shipping becomes less and less niche.
Oh there were definitely modern cartoons that started comedic/action and took a turn for darkness and/or drama hard, especially post gravity falls. Adventure time is the most obvious one, owl house, amphibia, other gravity falls clones, Korra (compared to aang), Star vs Evil (huge offender), Steven universe, etc.
Sorry, modern popular cartoons completely passed my mind since, unlike every other internet denizen, I pretty much haven't watched any televised cartoon since the original run of The Clone Wars because I'm an adult
who instead watches vtubers and maybe an anime now and then. I guess it's then just remarkable in this aspect how quickly HB transitions from comedy to drama.
Speaking of which, now 3 episodes into season 2, and it definitely looks like it's at the point in which I describe the show as being a drama foremost, ramped up compared to even the latter part of season 1. I've now seen for myself the full transformation of Stolas into innocent sadboi (while heaping all the villainy onto Stella) that has people here annoyed so much. Now with almost the entire main cast (except Millie) being fashioned into tragic, crying victims, a couple of thoughts have occurred to me that I doubt have been mentioned here before:
First, it's becoming peculiar how VIv wants so hard for the audience to sympathize with demons from
Hell. I place emphasis there because this setting is meant to be
the Christian Hell, the place of eternal damnation for sinners rejected from Heaven. Now story sympathetic protagonists of some sort of demonic origin are nothing new, but when I think about it, I'm realizing that such stories seem to have some abstraction from Christian Hell to become more palpable. There's two main ways of doing this that come to mind. One is by having the afterlife be an all-encompassing neutral zone rather than a place of pure damnation and evil, like the underworld of Greek mythology as portrayed in the popular video game Hades. Another example is the main Netherworld setting of the JRPG series Disgaea. The other is by having demons share no connection with afterlife or even theology, but rather originating from some fantasy dark world that is alternative to our own, a premise that seems particularly popular with Japanese media with a love for "demon lords", including the Devil May Cry series. Even ghost-themed stories like Ghostbusters and Casper are often abstracted enough from Christianity to have room for good, sympathetic spirits. Now a counterexample to this whole notion I'm presenting here is Helltaker, but it seems to me from the outside that it has practically no story, completely unserious otherwise, and is only popular for its character designs. Point of all this being that I'm getting the impression of Viv through her own work of how scoffing she may be towards the Christian concept of Hell, suggesting of what's to come for Hazbin.
Second, while there certainly is a lack of focus on the main cast's business as hitmen against humans, it remains as they're business that they are enthusiastically dedicated to, which ought to make them villain protagonists especially since they're maliciously encroaching on the human world while their fellow demons apparently ordinarily do not. Now villain protagonists in cartoons can be quite popular with examples such as Invader Zim, Pinky and the Brain, and even Ed, Edd n Eddy. A common trait among these shows, however, is that the protagonists often face comeuppance for the villainy they strive for. In contrast, the HB cast appear to be constantly emerging victorious in their conflicts, frequently with violent glee. You'd think that Blitzo especially would be a karmic punching bag as the standout asshole, but nah, in the end he gets fashioned as a cool guy instead. I wonder if the oft-mentioned absence of hitjobs in the show is a conscious effort by Viv to turn a blind eye to the despicable business of IMP to pass them off as heroes to the audience.
On a final note, I was joking before about the unusual frequency of gay dudes in the show, but holy shit I was still surprised by the introduction of even more, including Moxxie getting promoted from mere effeminate wimp. I'll at least give Viv credit for going against the seemingly usual handling of "bisexual" characters (when they're not outright sex freaks) to mean that they settle into a gay relationship after a straight one.