Sentence examples for a vanity project from inspiring English sources

The phrase "a vanity project" is correct and usable in written English.
It is typically used to describe a project that is undertaken primarily for personal satisfaction or to enhance one's image, rather than for practical or functional reasons.
Example: "The new art installation in the park is seen by many as a vanity project of the mayor, rather than a genuine effort to improve the community."
Alternatives: "self-indulgent endeavor" or "ego-driven initiative".