Not really “just a Flutter”. Technically Compose is more advanced and does a better job automatically diffing state changes and updating widgets granularly. On Android it doesn’t carry its own renderer but embeds into the native Canvas, which has both advantages and disadvantages.
What do you think SwiftUI views do when they need to draw to a surface in the end, hopes and dreams? They delegate to UIKit, which uses CoreAnimation, then CoreGraphics
Skia is just a cross platform abstraction of drawing toolkits, it goes through CoreGraphics too.
Rendering isn't magic.