I agree with the others' sentiments about it being like a lot of 2010's internet culture throw up. Also the color palette of the show is part of the aesthetic in that it's supposed to be so visually atrocious, and it reminds me of how Invader Zim relied heavily on colors that had to be mixed in specific formulas involving at least 3 or 4 colors (primary and secondary) in order to get their color palette which made the traditional animation so much more expensive. They wanted that sickly alien dark color palette, just like Hazbin Hotel wants and overly warm-toned red for Hell, but with the added pinks and neon evoking red light districts.
I was surprised at some of the changes. Velvette was supposed to look like a 2010's-ish Lolita Girl habitually on her phone. I was suprised to see the Lolita aspect taken away. Same for Vaggie, I remember seeing that she was said to have died in 2014 and was of Mexican descent, even speaking Spanish for a short moment in the pilot. These aspects just seem to have been entirely done away with.
I was jarred by the change in gears from the Pilot to the first two or three episodes. The Pilot set up the story in such a way that I thought it would be at least a full season before they ever got any sign or interaction from Heaven, and would go through localized growth as a group within the hotel and Hell. I thought we'd get more exposure to the culture of the Pride ring and the ruling classes, and Charlie's relationships with everyone and her personal growth. I felt robbed of that, especially when Adam was introduced in like the second or third episode.
I think the songs felt like bandaids slapped on to advance the storytelling instead of having better writing and interactions between the characters.
But you know what? I'm amazed a show like this could come to be in a way like this, and props to the team for their persistence. The show doesn't feel as polished as other animated shows that come up in a traditional way. And it is speaking to the 2010's teenagers, and evoking elements from those time especially in online spaces. It is interesting to see a more "mainstream" child that developed out of the non-mainstream cultural influences of the time.
But my big issue with something like this being in the "mainstream" is that the 2020's teenagers are being exposed to content like this as part of their "mainstream". I have a younger sibling who is far enough apart in age, but close enough that they talk to me some about these things. Back in the day, we watched Gravity Falls together. I wash just young enough to be into it and old enough to solve the riddles, and they were just old enough to watch it and understand the story and enjoy it with me. Now they've continued watching Amphibia and Owl House, and other adjacent shows. Hazbin Hotel with its dynamics and character designs is an artistically adjacent show in this time frame and in fandom spaces. Back in the day (I'm getting older, ew) we had shows in fandom spaces that had great heroes journey's and moral lessons... But the raunch and subjects like SA and the shipping (I lived the time in fandom culture before "Antis" or "Anti-shipping" advocates appeared) existed almost solely within the fandom online spaces. Unfortunately, because of the attitudes of the time, a lot of the mainstream popular media (Doctor Who, Naruto, MLP, Marvel, Supernatural, etc etc etc) would not touch LGBTQIA+ pairings or feature them as part of main cast, so those ships and pairings also existed mostly within that online fandom space. The online fandom space, especially FanFiction spaces, were a space where a lot of 2010's teens and college-aged adults vented and expressed themselves, and especially a lot of queer youths. Back then, there was a lot of fanfiction and art involving subjects like SA coming from real people who were either fetishists of it, or actually struggling with these things, or just drawing them to exploit the subjects for money because there was a market for the content (as gross as that is to say).
I was so happy to see a show like Owl House come out and get to be mainstream. Hazbin Hotel to me is the ugly flip side where I can see those direct influences of that online fandom space, and the show doesn't make any effort to deal with these topics in a healthy way or a way that has evolved from that time frame. It deals with them in an exploitative manner from a professional animation perspective. It's like they took a gay SA vent ship fanfiction story and slapped it on the big screen for profit, or out of fetishization. And that's my take on it.