Samsung Galaxy S8: How to Change the Keyboard Size (Big / Small)
To adjust the keyboard’s size on the tablet, go to Settings, followed by General Management. Tap on the Language and input option; that’ll be the first one on the list. Once you’re in, look for and tap on the On-screen keyboard option; tap on the keyboard whose size you want to change.
How to Enable/Disable Gboard Floating Keyboard on Android
https://www.youtube.com/watch?v=GTUcMjz-Djk