TimeSpanUtils.cs

public static string FormatTimeSpan(TimeSpan timeSpan)
{
    var (minutes, seconds, milliseconds, microseconds) = (
        (int)timeSpan.TotalMinutes,
        timeSpan.Seconds,
        timeSpan.Milliseconds,
        int.Parse(timeSpan.ToString("ffffff").Substring(3))
    );

    return $"{minutes}m {seconds}s {milliseconds}ms {microseconds}μs";
}