Hmm, the basis of these so called naming conventions you mentioned do not exist in reality ...
-large parts of Belgium were carved out of LuxembourG, not the other way round
- there is officially no such thing as North Korea or South Korea. They are called Democratic Peoples Republic of Korea and Republic of Korea (similarly Taiwan is Officially the Republic of China, while the mainland is called the People’s republic of China)
- similarly, what was casually called east/west Germany actually were German Democratic Republic and Ferderal republic of Germany
- In the case of the Sudan, the official country is called Republic of Sudan, while the newer entity is called the Republic of South Sudan
In all cases, both entities always recognize their shared heritage, so they do not dispute each other’s names. That isn’t the case of Macedonia. While geography wise, FYROM was part of the Ancient Macedonian kingdom, the current population of FYROM are ethnically Slavs who only settled there in the 6th century AD and have nothing to do with the Hellenistic ancient Macedonians. That’s what the Greeks object to and especially because their northern neighbour uses it in an official capacity (and not casually). I believe that’s the crux of the issue as far as the Greeks are concerned.
On your other stuff about Kashmir, bengal, Punjab... I don’t see the point of those, but it isn’t relevant either way to this issue between Greece and FYROM
