Any other author could’ve turned the Knights of God into iconic antagonists on par with Akatsuki, Phantom Troupe or the Espada. Minimum as good as the League of Villains
But of course we get Oda instead
No they couldn't have lol
The Knights of God were
introduced in the Final Saga of One Piece
Let's see when the factions you mentioned were set up or introduced:
The Akatsuki were setup/introduced in Part 1
The Phantom Troupe were setup from the beginning and fully introduced in Yorknew City (early-midpoint of the series)
The Espada were introduced in Hueco Mundo which again is the middle point of the series
The League of Villains was something Horikoshi built to throughout the entire manga
The only comparison you could make are the Warlords or the Admirals. None of the factions you listed (or can name) were introduced near the
end of the manga and hit the same highs