https://javascript.plainenglish.io/how-to-find-the-caret-inside-a-contenteditable-element-955a5ad9bf81

getCaretCoordinates rect:
DOMRect { x: 323.066650390625, y: 231.93333435058594, width: 0, height: 17, top: 231.93333435058594, right: 323.066650390625, bottom: 248.93333435058594, left: 323.066650390625 }