This suggests that, if you look across the top row of the keyboard, you might find the resize icon that you need to get back to normal: https://support.google.com/android/thread/41330392?hl=en I've just taken a look at my own phone (Android but not Nokia) and there's a 'resize' icon that can be accessed by initially tapping on three dots.
21:03 Thu 03rd Sep 2020