Why do we have so shitty dragon main characters?

[panzerkampfwagyu]

Spoiler: Warning, NSFD

I'm leaving this here as a honey trap for any dragons on the Forum.

 

[Momaiscree]

This thread is downright deranged

 

[BakedBanana]

This thread is downright deranged

Not as deranged as the user who brought this back. You are playing with fire bro, or should I say playing with the Necronomicon.

Source: Menhera-chan (chapter 1)

 

[wandere]

Usually you can have your answers by checking the nature of a comic.
Is it an adptation? Is the light novel an adaptation? Was it originally something from e.g. syosetu?
If all the answers are yes, then you don't get badass dragons because the authors of the web novel cannot write them.
Syosetu is the deviantart of japanese writers and the only reason their work is published is to get a quick buck while something is trending.

Now that I'm done with the rant, a more serious answer.
Having a proper dragon as a main character is not interesting enough to keep the plot up. A proper dragon is wise, all powerful, and so on.
You can only go so far writing something where the protagonist is able to immediately devise a solution and be sure to enact it thanks to its infinite power, before even you as the author get bored.
It's why dragons are more often than not supporting characters, like in Eragon (yes, I'm using western work. Current-day manga dragons are from the west, anyway) or they have something "debuffing" them like in DragonHeart (the movie) where the dragon co-protagonist is goofy and all.
I'm not condoning the absolute infantilization japanese authors have performed on these majestic lizards, but more often than not you are forced to tone their omnipotence down in some way.

So I flicked through this; mostly what you said; the Eragon Series (The Inheritance Cycle) is one of my favorite book series, and yeah Sapphira is...I want to give an opinion but I don't want to be wrong; I remember the dragons possessed a lot of intellect from birth (and some wisdom as well) and this feels like what the OP wants except...yeah it just would be kind of boring. I'm going to veer off a bit: So like, Solo Leveling. Solo Leveling has a protagonist who is 1. Badass (I dislike admitting it but true) 2. Very Powerful and 3. Very boring. He gets infinitely more boring the moment he loses almost all semblance of his personality prior to gaining the system and...well that's why I kind of don't like "badass" characters.

You need to give a character some flaws, something to work on, or if not that conflicts outside of themselves that test their character. I feel like the vision that's being aimed for here is like "Cool dragon that never loses a fight and is never wrong" and that's some people's wheelhouse; but in a critical sense I can't call that good writing or enjoyable outside of in a popcorn way. You could argue to just go the One Punch Man route and have a lot of supporting characters who are affected by the actions of this super powerful main character, but even in that case Saitama has a personality; it's not just all well drawn/animated fight scenes.

There's ways to work around it, it just is that the only way to work around it is to actually write a nuanced and interestng character that doesn't get to win every fight or be right in every situation.