Is the imam of the mosque, who wishes to leave the imamate due to living conditions, sinful, despite the people of the neighborhood needing him?

If a man is knowledgeable and needed in his neighborhood, then teaching is an individual obligation (fard ayn) upon him. If he moves to another mosque in the same town, there is no harm. However, if he moves to another town out of necessity, such as seeking sustenance, there is no blame upon him, and the community should look for a replacement for him or help him to complete his mission.