Flutter is purely a UI toolkit. It takes a rectangle from the OS and draws everything inside, like a game would. It just happens to copy Android/Material design

Flutter is purely a UI toolkit. It takes a rectangle from the OS and draws everything inside, like a game would. It just happens to copy Android/Material design and iOS design. The point is to to provide a reactive UI system. Focus is converting objects to fast 2D drawing. Kotlin multi platform as described here has no UI system, it’s a way of compiling Kotlin to binaries that are easily linked to both Android and iOS apps, with some bridging back and forth conversions into the native systems in each case. You’ll still need two separate code bases to call the common binary and handle UI.