This idea does NOT work for iOS 15.2.1 on an iPad Pro.
The wretched Floating Keyboard Icon remains no matter what the status of the Settings > General> Keyboards > “Shortcuts”
I have submitted feedback on the official Apple webpage listed elsewhere in this thread.
It's not likely to be fixed, because this complaint rides upon underlying cultural problems with Apple:
1) They do not test new features properly with real users and real iPads
2) They force new features on the weary uninterested public, without providing individual options to turn them off.
Mark Passio at WOEIH was stating that at one point Apple had a 24/7 telephone hotline that you could ring up, a real person would answer and stay with you until your tech problem was fixed. At £1000 for each iPhone or iPad, and $3T current assest in 2022, you'd think Apple could easily still afford that service level?