Based on previous experience, the optional HEPA filter seems to work, but many users find its benefit rather low due to the small filter surface. If better air purification is important to you, a separate air purifier is usually the more effective solution.
Here's a link to the filter 😊: https://www.galaxus.ch/de/s2/product/midea-hepa-filter-2x-zubehoer-luftbehandlung-54670793