okay so like you know how the striders are all cool and dont show their emotions n shit right
and we dont know much about the guardians canonically, and get most of their characterizations from their younger alternate selves right
well beta!dave wants to hide his emotions like bro, bc he looks up to the guy, and bro is all stoic and cool and collected, but you see in quite a few instances in the comic that dave is actually quite expressive when hes not actively trying to be a dweeb coolkid
so my headcanon goes that alpha!dave is the same. hes expressive, but he doesnt understand if his dirk (term used loosely as this is a multi-verse/multi-ship blog) makes it out like dirk learned to hide emotions from dave himself
bc inside dave's head, he's like "where did he learn this i never taught him this what is he talking about im affectionate as hell thank you very much" bC HE IS
it's just that he's always away, fighting in the resistance against HIC, where he has to play strong, collected leader, and tries to downplay negative emotions as much as possible when the public eye is on him to keep morale up, but also war isnt exactly his happy place, so he doesnt smile either
and even before that, when he was doing premiers and movie shit, he'd be all business, mostly, and he only just barely smiles (if he even does) for photos bc the paparazzi is annoying and tiring af
so we come to the conclusion that dirk probably thought that that was what , dave was teaching just by example, bc dave is rarely around, and most of what dirk sees of dave is how the public sees him, and thinks that that's what he's also like in private
tl;dr, my alpha!dave isnt emotionless, he's expressive in his own way, and if he interacts with a dirk who makes it out like he learned to hide his emotions from dave, it'll puzzle him, bc dave knows he's not like that at all in reality :^)
congratulations if you've made it this far into my rambling