I've always thought it would have been interesting if O'Brien had also belonged to a completely different social group.
It would kind of make the best use of the fact that the main characters only hang out with each other, by at least suggesting other stuff is going on.
Miles would say things like "I can't tonight, Manny Petorsky's band is playing in the starboard rec-room."
So much of this right here! ^ Kind of like "Lower Decks", except not that much lower. My only gripe about Lower Decks is I honestly thought that Nurse Ogawa had been on the ship so long that it would be quite unlikely she'd hang with Lavelle, Jaxa & Taurik, who all seem like they might have been recruited about the same time, maybe even in the same academy class. Ogawa is older that that right? I really never considered her a junior officer, like them, at that time. It's never stated, but she sure did seem like the chief nurse. If I were assuming a social group for her, the non-coms & civilian workers like Keiko & Miles would be right in that wheelhouse
As for Miles & Geordi, I agree with 2takesfrakes. I'm sure they'd very much like one another, both being very friendly, down to earth guys, but as for socializing? I dunno. Geordi seems like he'd be very wrapped up in tech hobbies, whereas Miles, even though he's exceptional at tech stuff too, his hobbies & free time is spent almost completely the opposite of that. They're both good guys, but not very similar people
It might be no coincidence that Geordi's best friend is an android

Actually, as for a human best friend. I think Geordi should just stick to running with Barkley & Wesley... You know, the geeks. Miles isn't one of the geeks. He's one of the dudes. lol. Actually, until he got married, I could sort of see him palling around with Riker. Riker actually needed something like that too, to bring him down to Earth a little, & make him seem less pompous, a buddy might've helped there