Hello.
I am looking for manga suggestions where a male and female character establish such a good dynamic with each other that they are a couple in everything but name; they don't need a confession, kiss, marriage end, etc. to show that the two are together. I would prefer no constant emphasis on romantic interactions between the two, but if it occurs here and there, it's no big deal as long as it doesn't become the main focus.
Examples:

I prefer seinen, but all other demographics are fine. Can be ongoing or complete. No yaoi/BL or yuri/GL please. I tried doing tag searches with the subtle romance and romantic subplot categories, but found most series ultimately had a large focus on romance.
Thanks in advance for recommendations.

shin and noi from dorohedoro

Looking at your lists, you've already completed it, but I feel this is the case in Eyeshield 21. Listing in case anyone wants to read it.

Raise wa tanin ga Ii fits your description of good dynamics

technically they are a couple so i guess that goes against what you’re looking for but it’s an arranged marriage of some sorts. My explanation probably doesn’t do the series any justice HAHAHAHAHHA

Thanks for the suggestions. I've had Dorohedoro on my backlist for a while, so I'll read it as soon as I can! I'll try Raise wa Tanin ga Ii regardless.

More suggestions are appreciated.

Bumping for suggestions.