The article is somewhat sensationalistic. Finding an octagonal type bronze sword ("Achtkantschwert" in German) from that period is rare, but we have quite a couple of them. Since bronze does not rust, the conditions of such swords are often quite good (and typically far better than that of medieval iron swords, for instance). Here is a map of the distribution of octagonal-hilted swords in Europe: https://www.research…
My knowledge of bronze vs iron comes purely from playing dwarf fortress. Are they fairly comparable in the damage they can cause?
It's not quite like the D&D "this metal is higher ranking and does more damage".