my typical answer is Data, from Star Trek: The Next Generation, but I've gotten a little tired of talking about him...

though someone who's been rapidly rocketing up my list of favorite characters (or favorite Star Trek characters, at least) is T'Lyn! she's the sweetest Vulcan there is, using logic and science to deepen her friendships and thinking less rigidly than most Vulcans. the current season of Lower Decks makes her into a full-fledged member of the main cast and it's giving her so many great character moments. I didn't think I could like her any more than I already did going into the latest episode, "Fully Dilated", but that ended up being one of the best episodes of the series, with plenty of great moments for her!

(don't ask me why it's an AVIF)