Migrate or Die

You play a senior C++ developer with experience in gtkmm who has been hired by the Inkscape project to perform some of the essential steps of the GTK4 migration. Time is running out and you must use your strategy skills to quickly migrate the codebase while avoiding conflicts with other work that touches the user interface. You'll need to work closely with the Inkscape expert to ensure a successful migration before the deadline. The clock is ticking, can you migrate or die?