I used “Balkanize” loosely for the many invasions the Romans in the western provinces couldn’t hold against, and the influx of foreigners, diluting the WRE (western roman empire).
Balkanization proper, started centuries later.
The influx of foreigners - Vandals, Visigoths, Ostrogoths, Franks, Burgundians etc. didn’t change the culture - ultimately all of these got assimilated in the higher culture of the Romans.
Also these were large groups of people but miniscule compared to the base populations. Which is why the Frankish empire ended up speaking a Latin tongue as did the Visigoths. And why the Turkic speaking Bulgars became fully assimilated by the Slavs they ruled