heyhey!
I exclusively write in third person because that’s just most comfortable for me personally and I think for a lot of other people, too. I also try to stick with present tense because that makes things for smut always more immediate and needy.
I would use MC (Main/Male Character) or DC (Dad Character) for the dadsona name and also just handle it as if it were the name (”Hey, Robert. DC just told me about that one time you went into the cinema…”)… however, I would not shy from writing in tidbits that relate to your personal dadsona? I think it would be super neat and flesh the character out a little more.
if you are concerned people don’t get it (usually they do, though… they will understand that all things written about the dadsona will be inferred to by the author if it has not been explicitly stated in game), I would make a short intro before the ficlet starts of ‘hey I’m using DC for the dadsona and a few of my headcanons’.
I think personally this would make a good compromise of you still writing your character but it not absolutely feeling like an OC, because I know that I personally never read OC fics because they make me uncomfortable. But if there’s a certain kind of anonymity to it, I would probably read it!
all these tips are only what I personally feel though; I can’t speak for everybody obviously.
bottom line is, if you feel more comfortable writing your dadsona’s name, or writing in the first/second person, then please do so. Nobody would be mad or disappointed, and it is your fic, after all.