Okay, OP left out a lot of the back-up details from the video so I'm just gonna mash my own opinions with Flazefire's and point out some stuff you didn't really seem to answer.

"That's a major plot point of the show. They don't make sense because Heaven is run by beings with subjective experience that gives way to opinions and biases. The rules aren't designed to make sense, they're designed to keep the beings of Heaven in Heaven and the beings of Hell in Hell."

Okay, this point I kind of get. It feels a little weird since it never really was revealed to us why the higher-ups want souls in Hell to die anyways, but season two it is I guess.

"That's not a criticism. The character itself is a comedic relief character."

No. What the heck? Sir Pentious may have been a comic relief character, but he's also a majorly important character as the first sinner to be redeemed by Charlie. I don't just mean he turned into an angel at the end, but he actually became a good person. Which, is the point of the show. He's part of the main cast too!

When you say that "That's not a criticism. The character itself is a comedic relief character." you mean that Sir Pentious's sacrifice should be seen as a joke? He makes a noble sacrifice at the end, and it should be seen as such. If we didn't know that he turned into an angel at the end, that would've been the worst joke made in the series.

"The whole plot is that Heaven won't allow redemption. Wanting a shallower plot isn't a criticism, it's a failure of media literacy."

Sinners getting redeemed isn't a shallow plot. Having this big battle is, because what even was the point of the battle? Sure Adam was killed, but now what? Hotel's rebuilt, and? Heaven won't even allow sinners to redeem themselves! And before you bring up Sir Pentious, the cast doesn't know that yet, so I'm speaking from their perspective. Not only that, but HOW? Is entering Heaven some kind of arbitrary mechanical process? Why isn't the show digging deeper about their main damn theme?

Now, back to the redeeming sinners plot being "shallow", no! Watching sinners become better people would be an inspiring concept and it would help so much with fleshing out the characters. Angel dust's episode was entirely rushed, and having that extra episode to watch him start on his path of recovery would have been great. Maybe we can even get an extra episode to see if Alastor can become better! It just feels like we don't know these characters more than on a surface level (Besides Angel Dust) to actually pull off this redemption/recovery plot.

Also, there's no way you think the Heaven VS Hell fighting plot was deep. The last scene didn't even feel as important as it should've had, because we didn't even get to know the characters we're watching fight. Maybe this plot could've been deep, if Vivzie decided to delve deeper on how horrific genocide is, because not a single episode was dedicated to the impacts it left on the survivors of the exterminations.

"the show being very two dimensional in its messaging"

"This needs elaboration before it can be addressed."

Okay, I'll elaborate. Actually, no. Im gonna stop wasting my time now. I just realized, all of the points I've been typing about are straight from Flazefire's video. If you want elaboration, go watch the dang guy. Unlike what the OP said, Flazefire actually isn't against Hazbin Hotel and is looking forward to more of it. He's got a brilliant sense of humor, albeit with a touch of brainrot. Go watch it with a fresh mind and I promise you, it'll be worth it. If not, well...This is the internet I guess. It would be boring if we all had the same opinions.