Hotel

It's probably an asset downloaded from thw web.

If you draw webtoons that have strict deadlines, it would be hard to draw all the backgrounds manually all the time. Takes so much time. So most webtoon artists use the free/paid 3D assets such as buildings, transportations, homeware like sofa, bed, etc, and tweak them a little bit to fit their art styles. All they have to do is placing things here and there, set the perspective, and maybe change some little details. It takes shorter time than actually draw all buildings in every panel and stuffs themselves.
Some authors might pick the same building designs, therefore the same building appears in a lot of webtoons.

If the webtoons have their own well-cooked worldbuilding, tho, they'd probably build a 3d model of the backgrounds themselves or hire a professional to build it, then use it the same way as the downloaded asset I explained before.