For reference: the baths in the city were destroyed exactly a hundred years later, in 375 CE. So odds are that the fort was mildly effective to keep the barbarians out.

And by “barbarians” I mean likely Franks. In the long term… well.
Image

This is a map of the Franconian dialects. I edited it to show Aquae Granni / Aachen, right in the middle. “Franconian”, “Frankish”, you should get the picture.