I'm 3/4 of the way through Age of Calamity so far, and unless it takes a nosedive in the final 4 missions, it has my vote.
I like the art style of the first game better, but AoC has much more varied gameplay thanks to the runes and elements plus the Divine Beasts, plus a better story.
I like both but for me the first game's a 7/10 to Age of Calamity's 8/10.