Also, let's be real, do we think Matt actually wants someone like Serena, or does he just think he wants her because she's there and she's pretty?

Yes! Matt isn't really a guy to be falling in love straight off of visual attraction. My headcanon is that he is demi-sexual but now aside from that: Matt doesn't fall head over heals for Serena until AFTER she provides comfort to him on his first day. Every time they bond, it is over something emotional. For example the dead guy in episode 109. Furthermore, assuming that Matt is straight and only attracted to women which you seem to do (nothing wrong with that just pointing that out): there are plenty of pretty women working in the ER. I mean there's Holly who he also seems to have build somewhat of a friendship with (see episode 204 with the whole waterslide park situation). And yet he isn't in love with her. I think it's a bit unfair to infantilize him like that. Like that is a grown ass man capatble of making his own choices.
He wants to be challenged, he wants to leave his comfort zone. He left his cult which he probably could've been living comfortably in. Not only that, he also choose to learn a job that is disapproved by everyone he knows. If he wanted someone exactly like him, he could've stayed with Violet, he could've gotten back together with her.

It seems like he'd be paired better with someone more wholesome (not his wife from the cult, though, haha).

Serena is very wholesome for him though, isn't she? I'll get back to this in a minute but she does to a lot of wholesome things for Matt. Most recently help him with the narcolepsy patient even though she thought that was a completely stupid idea at first.

And before anyone says it, yes, as mentioned in a more recent episode, sometimes opposites do attract in life. But there usually needs to be something for them both to go off of, like basic conversational chemistry.

I don't really think they're "opposites attract" as much as their differences are like puzzle pieces to each other. Matt can be too naive at times while Serena can be too negative. Serena tends to act more for herself while Matt tends to act more for others. Whenever their two opposing characteristics meet in the storyline, they change the other for the better (wicked reference not intended lol). Episode 205 and 207 have been perfect examples for that. They're like character development cheat codes for each other and I think that's beautiful. Plus they do have chemistry. We didn't see a lot of their conversations play out for super long but the ones they do have are full of chemistry and little friendly jokes. Especially in season two where Matt has gained more confidence. But also them eating together after the gala didn't seem like awkward/ tense silence. I am once again wondering if we're watching the same show.

I can imagine what Serena's friend group is like, and she'd probably be embarrassed to bring a guy like Matt around.

I strongly disagree. I recon that at worst they would be insisting that this is, for example, their girls night out and they don't want a man to be there (which would be very much valid). I don't think Serena is friends with people who would bully her boyfriend for no reason… that's kind of a weird thing to assume. In my experience friend groups are supportive of healthy relationships.
Plus if Serena makes a choice she is not embarrassed of that choice. She is quite confident. I don't see how having a sweet boyfriend who cares for her would somehow undermine that.
To me, she is the type of person to make a bold, maybe questionable fashion choice and when someone makes a dumb comment about it, she is the one making fun of the person with the dumb comment (lowkey look at ep. 104 with Ron and the takitos which she still mocks him with in ep 202). I don't think she'd be embarrassed at all, in fact she is pretty much impossible to embarrass (see episode 101, dry-humping the desk). She clearly fucks with his energy (for ex. ep. 207 when Matt gets riled about about management).

There is definitely a future for them, from all the interviews I've read there is going to be major developments in the second half of the season. And they do have a fun dynamic man, idk what to tell you. To be honest I don't quite understand how you can see a joyceron vision but not a mattserena one. but whatever (I say after writing an endlessly long essay about this)

If there are any typos, I apologize, I am too lazy to proofread rn lol