Nobody’s doing it like James Cameron. No other blockbuster-forward auteur still infuses their impossibly massive adventures with his level of heart-on-sleeve earnestness, nor do they match his rigorously structured action sequences that soar on the highest level of technical wizardry in the industry. “Avatar: Fire and Ash,” like its predecessors, is nothing short of a miracle in an age dominated by lackluster, half-hearted attempts at spectacle. This may make “Avatar” sound like nothing more than water in a desert. In a way, it is. What makes this bugnuts, hyper-culturally insensitive trilogy about feline-esque blue creatures and their wondrously natural alien world stand out in today’s cinematic landscape is exactly what critics of the first film dinged it for back in 2009. Cameron’s unwavering commitment to realizing mythic archetypes through pinpoint precise artistry and broad emotional strokes painted across bulky three-hour-plus runtimes is exactly what’s so refreshing in today’s...