I’m not able to translate and delve into all of your post.
However, with regards to what seems to be your initial question about “why is Cmaj7 appearing as C7 instead”, what are your settings in Engrave > Engraving Options > Chord Symbols? There are many, many options for how different components of chord symbols appear. There’s a note at the end of the task for inputting chord symbols that mentions that the ultimate appearance of chord symbols in the music depends on these settings.
You should go through those options and customize them in the first instance, as if the option exists, it’s likely changing that will be much easier and quicker than editing chord symbols in the editors.