Q.Lemon Plant Disease? How to Fix
My lemon’s leaves look dry and not shiny at all. Not sure if it is a disease or lacks nutrients. Please advise.

If the leaves seem dry, check the moisture level of your plant. Citrus need even, regular moisture.
Watch for any other signs of stress or disease.
These articles have more information for you to help optimize the care and what to watch for in common issues with Lemon Trees.
https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1492.pdf
https://www.gardeningknowhow.com/edible/fruits/lemons/how-to-grow-a-lemon-tree.htm