From just reading this idea, Ai-chan doesn't think it will work out well. But just because Ai-chan says so doesn't mean it won't work at all. Ai-chan has no idea how your writing skills are and maybe you can make it work. Ai-chan won't be able to make it work.
Some flaws:
1. Chuunibyou
The problem with chuunibyou is that its existence instantly makes the chapter cringy. Now, just because it's cringy, doesn't necessarily mean it's bad. If you can make it the non-bad cringe, such as making a comedy, it could work. For example, in To Be The Power In The Shadows, the protagonist is an extreme chuunibyou and a massive cringe. What makes it work is that his aim creates a gap in his personality, one of the typical average mob character while the other is the super powerful anti-hero character, and as an anti-hero, his cringe is funny.
There's a little problem here. It could be said that I'm addicted to chuunibyou and I want to put it everywhere. I mean, it's not that bad, but I just want one of the main characters in that novel to be a chuunibyou. I don't think it's a horrible idea either way, she's not even the protagonist. I have not read the novel you mentioned, so I'm not sure I get the reference, but I don't understand why people think chuunibyou is cringe in general. Take Rikka for example, probably the most popular chuunibyou character out there. For me, she's pure cuteness. Sure, she would be cringy if she were real, but she's only an anime character. That said, I understand why a slice of life/romance novel would try to be realistic, but this novel with supernatural powers isn't really aiming to be the most realistic thing ever.
But... the truth is that chuunibyou is considered cringe in general, and I can't help it. I often see people describing even Rikka as such, so I have to assume that it's going to be cringe no matter how cute it is for me. I haven't specified it yet, but she's going to be the silent type of character, as opposed to Rikka or Megumin. When she wears that suit, she talks big and such, and it actually makes her quite powerful so there's nothing chuunibyou in it. The thing is that after it's destroyed, it is revealed that she's actually a little girl that has great ambitions, but an incredibly weak psyche. She was most likely scarred in the past and it caused her to hate the entire world, want to destroy it. One day, she received the power to do that and it made her come up with that antichrist thing. It's supposed to hit a soft spot, but I'm worried that it won't work on most people.
2. Big titties
While big titties is not a big deal, you specifically mentioned big titties and flat chest, so Ai-chan guesses you will just do the same thing every other people has been doing. Which is to massively dump big titties vs flat chest comedy moments and interactions, which is overused. Sure, you can still make it work, but if you only do what everyone else already did to death, your readers will most likely be bored. Like, how many times can you say "You smell of cow milk" or "Flat is justice"?
No, no, no. I absolutely hate this type of jokes and I would never use them in my own novel. The titties are... just for being there, I guess. Personally, I'm not a fan of titties, so I wouldn't mind making all characters flat or just not mentioning chest sizes at all... but that would be kinda empty. I'm not even sure why I mentioned it, it's not like it's important or anything.
At first, I thought that this idea had some chances of becoming a success since it mixed originality with some popular tropes, but I may have been wrong. I never actually know until I publish it, so I might try this idea out soon either way. Even if it doesn't make it to trending, I'm satisfied as long as there is anyone reading it out there. I don't like all the isekai or smut stuff that's popular here, and I don't want to write something I don't like, so I tried to come up with something that may entertain the public and satisfy me.
The thing I'm writing right now, even though I think it's pretty much trash, there are some people reading that. Moreover, it's a slice of life story, so something totally niche on this platform. Yet someone reads that, even though it's my first novel ever. So I would be surprised if that idea totally flopped. Thanks Ai-chan for your opinion.