You copied that text from your cousin Bruzmi. He has a brain, I'll grant him that.
There doesn't seem to be archeological evidence that the population of Iader was anything other than Liburnian. Iader was a major Liburnian archeological site. It wasn't Delmatae or something else.
The V13 find in question is Roman, nothing Liburnian/Illyrian about it. Iader was settled by Romans already in the time of Octavian (40-30 BC), so there were real Roman settlers there in significant numbers.
Why wouldn't he be part of the movement of the so called Pannonian-Urnfield which affected that zone and via ships they sailed to South Albania and Greece as Albanian archaeologist Frano Prendi noted. The core Illyrian Glasinac-Mati complex was left untouched by this movement as noted by Matzinger and Lippert book on Illyrians 2021.
If he was a Roman, he would cluster a bit more toward Central Italy. Roman war with Batos happened around 7-9 A.D. So no more than 1-2 generation admixture with local people after this event, that would still show some kind of pattern about his origin something which this sample lacks. Though Odrysian-Thracian cavalrymen were crucial on winning this battle for Romans against Dalmatians they just smashed the Pannonian-Dalmatian rebels when they wanted to plunder Macedonia, i don't think they cared much on assisting Romans in Dalmatia hinterland.
Anyway, let's not rush on conclusions and probably we are lucky enough we get some Iron Age samples.