This is probably not an expected choice because there are few scenery shots & the ones that are present are not necessarily impressive, but the Reply Series always marks me with the ornate detail and sheer work they put into the super intricate sets and creating the time period they are presenting. So if you're impressed with production values in general, this could fit, but, again, there are no impressive landscapes or sceneries.
Some dramas that I consider really beautiful, aesthetically pleasing (that involve or are based around romance as per your request) are The Princess' Man, The Moon That Embraces The Sun, The Story of Ming Lan, Ten Miles of Peach Blossoms.
If you're willing to watch something a little bit older & thus a little bit more cinematographically natural, Dae Jang Geum is probably the closest thing you're looking for (STUNNING scenery & a lovely romance, although it does take a bit of waiting since the story is about her life from childhood on).