If that's the case, I propose viewing yourself as the main character of a Slice of Life anime.
It's okay if you're not the chosen hero, it's okay to just be some guy. You can still see yourself as a protagonist in this regard so by all means, root for yourself. But it's okay if your story isn't one about a magical third act where you're isekai'd and fighting demons.
I wouldn't call it a syndrome since that's a realistic way for people to think. It's not burdened by delusions of grandeur.
trouble with delusions of irrelevance is that we're closer to correct than the saps who think they're a disney protagonist.
If that's the case, I propose viewing yourself as the main character of a Slice of Life anime.
It's okay if you're not the chosen hero, it's okay to just be some guy. You can still see yourself as a protagonist in this regard so by all means, root for yourself. But it's okay if your story isn't one about a magical third act where you're isekai'd and fighting demons.
Be pretty cool if that magical third act existed though.
The worst delusions are the ones that have some basis in reality, because you can't reason your way out of it.