@sungjaywoo i'm guessing the person might be looking for a way to describe more of a feel for a story across any genre or theme rather than one specific one like romance. Kind of hard to describe, but maybe like a sub-category of slice of life. I've read one manga comment section where the story line was described as frantic, I kind of think of lowkey as the reverse. Can't speak for the OP but when I saw the thread title some mangas came to mind. For example:
Isekai: (maybe not having to save the world, or major characters that seem to be designed for you to hate like in Ichioku-nen Button o Renda Shita Ore wa, Kizuitara Saikyou ni Natteita. Basically just living life in another world. )
https://mangadex.org/title/21055/tondemo-skill-de-isekai-hourou-meshi comes to mind, there are battles but they never seem to take the full issue, it's not a soap, he's not fighting the demon lord where the world will end... https://mangadex.org/title/23706/kami-tachi-ni-hirowareta-otoko .
Romance: (i think of no real love triangles, no nut case characters like in the pashiri one. I would think just watching the romance develop, at least I've seen requests for that.)
https://mangadex.org/title/23825/senpai-ga-uzai-kouhai-no-hanashi
https://mangadex.org/title/21367/shunkan-gradation (couple ends up together, little events here and there, what I would call a false love triangle, but nothing life shattering, wouldn't describe it as frantic)
...
The OP should have stated better what they wanted, maybe they will edit their comment. The above is just my guess, but it is what I thought of even before opening the thread. If my guess it right I would love to see a tag that describes it but I can't see the tag working do to how hard it would be to define for everyone. So I would have to vote no.