AlienWarlord
The chapter was fine, but it was a bad read on Tony Stark character. He is the single character in MCU that could enhance himself pretty much any time he wants. Ex: extremis. He specifically created an improved version of it to get himself healed from heart shrapnel and not enhance himself. The only real weakness of Iron Man is tony stark, yet he doesn't improve on that. But its your fic if you wanna make Tony more like comics version of him.
They could possibly hide it even further by passing all the credit to a metahuman. Pretend they have a metahuman that has the ability to temporarily grant super strength. If needed Tony could even build a cyborg to fit the role. Doesn't need to look too human because he can wear a costume, with fits the whole superhero theme anyway.