Alright, this is an extremely subjective type of question, but here are some of mine with a couple thoughts:

• Sweat and Soap - This is probably the most spot-on recommendation I can provide based on what you said you are looking for. A romance between working adults that are able to do things like communicate with each other to overcome problems together instead of drawn out, contrived misunderstandings. It’s great. Also, I haven’t read it, but the author also wrote Telework Yotabanashi, which I have seen others say fits this profile as well.
• Love’s in Sight! - Reading the synopsis, you might question my recommending this because the characters don’t seem too realistic. However, despite heavily featuring a cast of characters with visual impairments, I was impressed with the realism with which they are depicted. I have professional experience talking with people suffering from visual impairments and the issues that the manga depicts lines up with the real-life issues that these people experience extremely well.
• The Girl I Like Forgot Her Glasses - The most unrealistic part of this series is that somebody with such bad vision would forget their glasses as much as Mie does. However, if you suspend your disbelief for that one narrative conceit, then this one feels pretty genuine for a middle school romance. I started reading this series rolling my eyes at Mie forgetting her glasses all the time, but that gimmick lessens over time and the story becomes more heartfelt and touching as it goes.
• Journey Home After School - This is the only ongoing series in my list and probably pushing your realism boundaries the most. However, if you can overlook some fun randomness from Chokki-chan, then this has so far been an excellent romance.