Not an answer to you actual question, but: I stopped using dead keys long ago because I found it irritating to have to hit space whenever I needed to break out. Instead I mapped my CapsLock to be a Compose-key which lets me make almost any symbol I ever need in a very intuitive wsy. It works everywhere (incl. Wayland).
This does not remember the position of each individual window, though. i.e. all programs will (still) open on the same position.