consider osamu was never good with words so whenever he'd want to apologize to people, he'd leave a bento box of food for the person somewhere he knows where they'd see.

whenever he'd have an argument with his parents, he'd make sure to prepare have breakfast for them the next day, even if that meant he had to wake up a little earlier than usual

he'd prepare atsumu some of his favorite fatty tuna and leave it on his bedroom desk before heading to school early as an apology for not telling him he's quitting volleyball after hs

whenever he and rin would have an argument, he'd make sure he made rin extra food for his training and a special love note on it with his favorite fruit snacks.

even to his workers in onigiri miya, whenever he'd lose his cool and scold one of them for doing something wrong, he'd make sure to leave them some onigiri in their break room.

long story short, osamu miya's love language is feeding those around him