Help! The birds don’t seem to be in paradise

My birds of paradise plant has a couple of leaves that have turned yellow. I know it could be down to a number of things but any advice would be appreciated

It’s watered once per week and it’s in a spot with not much sunlight (pretty much none). A few new shoots developed a few weeks ago so I assumed the light levels were okay

Is there a way to restore it?

Also some leaves have developed some white specks, not sure what they are ?