I think you’re right as to why he is hiding it from the hero. The hero is in the same sphere as like the duke, someone in a position of power who would be problematic if Satou ever revealed his heroic powers to.
Honestly Satou is getting to a point where even his non-hero persona is getting...
My view of the story thus far is that he has shown he’s moderately powerful. But in comparison to the hero party he doesn’t want to seem around their level because it will draw too much attention to himself.
Happy to see this translation start up again. Thank you! Sad it's such a short chapter though. It always feels like monthly releases start off long, but get shorter and shorter overtime.
This is the result of all the girls playing mind games with the dude. Hana had a good chance, but he's just so mind fucked and now he thought he made a huge mistake with his closest friend.