No new toponyms have been identified by linguists at the 6th-7th centuries. There is no new language and no new people. These are only old tribes who left their lands temporarily due to Roman invasions and returned after their lands were liberated with the help of the free northern Slavs-The Getae.
But we have new toponyms after the arrival of the Ottomans. How do you explain that?
I think and the new DNA here will be pointed easily.