Calamity War 10k years ago and the sealing of Ganon questions
I'm kinda confused about exactly how far back Zelda traveled during TOTK. For some reason, I was under the impression it was 10k years, but the Calamity War the Sheikah tech won was also that far back. If they are one and the same, then what was the point of the Divine Beasts and all that Sheikah tech? If they are separate, then that means that Calamity Ganon wreaked havoc some significant amount of time after Ganon was sealed but 10k years before 100 years before BOW, and was beaten by the Sheikah. That makes the most sense, however, it leads to another problem. Apparently, Calamity Ganon becoming active and destroying parts of Hyrule Castle 100 years before BOTW is what caused Rauru's seal to weaken to the point Gloom was leaking out, which inevitably led to him breaking free. If Calamity Ganon is what caused the seal to weaken, then shouldn't it have happened 10k years ago during the first Calamity War?
I'd just like some clarity on the subject cuz it feels like I'm missing something obvious, but I haven't been able to figure out what.