بِخِلَافِ النَّفْيِ وَالِاسْتِثْنَاءِ فَإِنَّهُ لَا الْتِبَاسَ فِيهِ
Negation with exception, by contrast, does not suffer from the same ambiguity.
Illā marks the retained term directly. Even when other constituents are advanced, the grammatical role of the term after illā can identify what is restricted.
مَا ضَرَبَ عَمْرًا إِلَّا زَيْدٌ
No one but Zayd struck ʿAmr.
The nominative ending marks Zayd as subject, and its placement after illā makes the intended agent restriction clear despite the earlier object.