Based on the floral features (short calyx, small abaxial flower, etc) and the single line of hairs on the upper leaf midrib, this is clearly Costus scaber, but in a form quite different from the usual in the region. It has much larger leaves and a thicker sheath and altogether a more massive plant.

UPDATE: 30-March-2021
Reviewing these photos, I now think this could be a proposed new species to be called Costus pseudospiralis.