my plumeria's leaves are turning rough on the surface, turning light green and then dying. But still putting out green leaves.
Certified GKH Gardening Expert
This looks like a fungal/bacterial infection. This is most common with overwatering, or the plant remaining too wet for too long.
From here you will need to fungicide. This article will help: https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm
This article will help you to care for the plant: https://www.gardeningknowhow.com/ornamental/flowers/plumeria/growing-plumeria.htm