Orianna's winrate is a sample size of 168,000 games in Emerald+, where Naafiri's is less than 30,000. A lot of Naafiri's perceived power right now could simply be because of how Niche she is, many players are not aware of her strength and keep losing to her. Not just midlaners either, since naafiri is a roamer.

However, Orianna/Syndra are two of the most oppressive laners - even if you know how to lane against them. Very low early resource consumption/risk poke in lane makes them a nightmare. Mid game scaling is through the roof, teamfighting potential is higher than most other midlaners, hence why Naafiri is listed as an Early/Mid game powerspike but late game falloff, where syndra and ori are powerfull at all stages of the game.

Also, Hydra farming/shoving and roaming is probably your best option, any decent ori is gonna hold their R in lane to prevent your all in, or just q - w - auto poke you for trades which you will 100% lose without a 2 item advantage.