The manga I’ve read with the most real characters by far was Skip and Loafer. It’s great! It’s one of my favorites! But honestly I’d say it’s only 1/3 romance with the other 2/3 being slice of life and coming of age. Still, I highly recommend it. The first season of the anime was also quite good, with the second season airing later this year.

If you want something where romance is a bit more of a focus I also recommend Wotakoi: Love is Hard for Otaku. It’s a story about a couple of awkward office workers who slowly develop their relationship.

My favorite romance manga though is Kaguya-sama: Love is War. These people definitely feel more like cartoon characters than people sometimes. Not in a bad way (I love how these characters are written), but their traits are pretty extreme for good and for ill. The first few chapters all follow the same basic formula, which might trick you into thinking that this manga is a one-trick pony, but it changes things up often enough that it ended up being one of the most satisfying manga I’ve ever read.