You won’t be able to do that in the submit method of the dialog component as that has no access to the editor (EDIT: although now seeing that you pass it as props so that could work, but I’d suggest still to follow my following suggestion - at least personally I prefer to have those actions in the mark file directly). Instead in the dialog open call in your mark, define on.submit handler that can then use the values from the dialog to create/update the mark.
Similarly like here in my example code: Adding a writer mark that opens a dialog for input - #2 by distantnative
Hope this helps to get you started in the right direction.