But you realize that getting all possible apps to look the same and have same behavior is very hard, you have GTK2, GTK3, GTK4 with their limited customization, then you have Qt apps, KDE apps, Java with their different GUI frameworks, node apps, Wine apps, other smaller toolkits used in Python etc.

But as you admit in Linux you have infinite more power to attempt setting up a global menu, but this feature is not something a mainstream distro offers by default so IMO is not a fair complaint.