Avoid the keyboard by leveraging additionalSafeAreaInsets.

updateSafeAreaForKeyboardFromNotification.swift

// Avoids the keyboard in a UIKit app by leveraging additionalSafeAreaInsets.
// You can put this in the root view controller so the whole app will avoid the keyboard.
// Only tested on iOS 13.3.
// Made for https://douglashill.co/reading-app/
@objc func updateSafeAreaForKeyboardFromNotification(_ notification: Notification) {
    guard let endFrameInScreenCoords = notification.userInfo?[UIResponder.keyboardFrameEndUserInfoKey] as? CGRect else {
        return
    }

    // Please consider whether the force unwrap here is safe for your own use case.
    let endFrameInSelfCoords = self.view.convert(endFrameInScreenCoords, from: self.view.window!.screen.coordinateSpace)

    // Need to clear the additionalSafeAreaInsets in order to be able to read the unaltered safeAreaInsets. We’ll set it again just below.
    self.additionalSafeAreaInsets = .zero
    let safeBounds = self.view.bounds.inset(by: self.view.safeAreaInsets)

    let isDocked = endFrameInSelfCoords.maxY >= safeBounds.maxY
    let keyboardOverlapWithViewFromBottom = isDocked ? max(0, safeBounds.maxY - endFrameInSelfCoords.minY) : 0

    self.additionalSafeAreaInsets = UIEdgeInsets(top: 0, left: 0, bottom: keyboardOverlapWithViewFromBottom, right: 0)
}