Cyrillic was literally byzantine propaganda, an effort by the Eastern Roman Empire(aka Byzantine Empire) to culturally assimilate/approach the slavs, in hopes for them to be friendlier to the Empire. Language and religion were the thing back then(and even today), having a similar language and religion made everyone friendlier.
Diplomacy, espionage, bribery, trading and huge ass walls were the strength of the Eastern Roman Empire.
Does PR want to be independent?
https://en.m.wikipedia.org/wiki/2024_Puerto_Rican_status_referendum
60℅ wants statehood.