Entity Framework - mapping

// *** Mapper class (with utility collection-mapping functions) ***

public class AudioMapping
{
    public static IEnumerable<BLAudio> MapToBL(IEnumerable<Audio> audios) =>
        audios.Select(x => MapToBL(x));

    public static BLAudio MapToBL(Audio audio) =>
        new BLAudio
        {
            Id = audio.Id,
            Title = audio.Title,
            GenreId = audio.GenreId,
            Duration = audio.Duration,
            Url = audio.Url,
        };

    public static IEnumerable<Audio> MapToDAL(IEnumerable<BLAudio> blAudios) =>
        blAudios.Select(x => MapToDAL(x));

    public static Audio MapToDAL(BLAudio audio) =>
        new Audio
        {
            Id = audio.Id ?? 0,
            Title = audio.Title,
            GenreId = audio.GenreId,
            Duration = audio.Duration,
            Url = audio.Url,
        };
}

// *** POST action that uses Mapper class ***

[HttpPost()]
public ActionResult<Audio> Post(BLAudio audio)
{
    try
    {
        if (!ModelState.IsValid)
            return BadRequest(ModelState);

        var dbAudio = AudioMapping.MapToDAL(audio);

        _dbContext.Audios.Add(dbAudio);

        _dbContext.SaveChanges();

        audio = AudioMapping.MapToBL(dbAudio);

        return Ok(audio);
    }
    catch (Exception ex)
    {
        return StatusCode(
            StatusCodes.Status500InternalServerError,
            "There has been a problem while fetching the data you requested");
    }
}