Hello @user0osbCw5noC ,
Thank you for your suggestion. You may try using Mini Pop up window in Phone app -> Menu -> settings -> Call display while using app -> Set it to Mini Pop up and Enable "Keep calls in pop-up". Mini pop up window can be moved around to any location on screen. Please note that, it only works if a call is received while using another app and is lost if you press home button.
One UI Beta Team