Keyboard mappings can be changed in the IDE Preferences/Settings: Select
Keymap, then enter flutter into the search box in the upper right corner.
Right click the binding you want to change and Add Keyboard Shortcut.

Hot reload vs. hot restart

Hot reload works by injecting updated source code files into the running
Dart VM (Virtual Machine). This includes not only adding new classes,
but also adding methods and fields to existing classes,
and changing existing functions.
A few types of code changes cannot be hot reloaded though:

Global variable initializers

Static field initializers

The main() method of the app

For these changes you can fully restart your application,
without having to end your debugging session. To perform a hot restart,
don’t click the Stop button, simply re-click the Run button (if in a run
session) or Debug button (if in a debug session), or shift-click the ‘hot
reload’ button.

Editing Android code in Android Studio with full IDE support