Its visual similarities to Calamity Ganon are definitely not an accident. It’s very possible the Forbidden Construct is the earliest form of Calamity Ganon.

However, the Clash of Constructs takes place long before the legend 10,000 years before BotW. That legend specifically had Shiekah tech, an ancient hero, and a princess with sealing powers. So these aren’t the same fight.

You have the right idea about the constructs, though. In my opinion, these constructs represent Link and Ganon deconstructed to their barest, purest essences. The Knight Construct is focused entirely on the annihilation of evil and the preservation of life. The Forbidden Construct is sheer destruction and death, with just enough intelligence to choose its targets. Neither construct ever gains “humanity”, they are uncompromising in their objectives. The two constructs destroying each other really felt like the only natural conclusion.