Once the leaves are damaged from a bacteria, fungus or insect problem, those spots will not change back to green.
The plants cells have been damaged. Nothing will fix them.
I am sorry but I don’t see any real problems.
How are you watering? How often do you water?
From what I see in your images, the media seems to be not really fresh. Have you ever repotted the plant? It could be time to do that.