"Immersive Settings" is an application that displays the screen in immersive mode by rewriting the system settings.
Software keyboard operates normally even in immersive mode.

# Caution
Before using this application you need to grant "WRITE_SECURE_SETTINGS" permission via ADB.
>> adb shell pm grant jp.sakeapps.immersivesettings android.permission.WRITE_SECURE_SETTINGS

Immersive mode will continue even after uninstalling this application.