"perfectly harmonious" is correct and can be used in written English.
You can use it to describe something that is combined together in a pleasing and balanced way. For example, "The melody and lyrics of the song were perfectly harmonious."
During a panel discussion the composer Derek Bermel said that he had found it almost painful to "rip the music" of "Sorry/ Grateful" from its perfectly harmonious lyrics.
Ballet's heroes and heroines wear clothing, and yet they deploy lines, positions and phrasing so that they too may project an image of the body as perfectly harmonious and apparently flawless.
Our class on leadership teaches that an organisation is not a perfectly harmonious entity; it is made up of a multitude of individuals with goals and visions that do not always align.
There's a black, high-shine 1960s sofa here, oil-painted portraits of King Baudouin and Queen Fabiola of Belgium in gilded frames there, all of which form a perfectly harmonious and relatively domestic counterpoint to a sense of industry and modernity that is also very much in evidence throughout.
Though it is a tiny outpost - six square miles between mountain and sea; a scant 800 or so people residing in perfectly harmonious homes (thank those tough building codes) - it became a hugely stabilizing force in de Betak's wildly peripatetic life.
In this he was, of course, developing the Stoic sense that if we could see the world as God does, as the perfectly harmonious embodiment of the logos, we would recognise how its apparent defects in fact contribute to the goodness of the whole.
Ms. Kikuchi's arrest has forced many here to relive an episode so bizarre and unsettling that it altered the way Japan sees itself, shattering the nation's postwar myth of a perfectly functioning, harmonious society.
Walking through the show, one museum-goer said, "We're really in for it, aren't we?" Despite the apocalyptic scenario prompting the challenge, the renderings themselves are cheery, showing a New York that is not only perfectly racially harmonious and clean, as rendered cities are wont to be, but also green, lush, and, thanks to a few key developments, dry.
I think it's the most harmonious and perfectly balanced gin around -- it makes a sublime martini and goes quite well in just about any other gin cocktail you'd care to imagine.
A few store ingredients to make it, some good shop-bought vanilla ice cream or heavy cream to eat with it: a perfectly balanced dessert to end a comfortingly harmonious meal.
Still, at the Olympics, we've come to expect elegance in victories, from Katie Ledecky's harmonious freestyle stroke to Simone Biles's perfectly executed vaults to Wayde van Niekerk's effortless-looking stride.
