Emoji unicode character '' is not beeing rendered in TextBlock

Question

I used the following method (original source: https://itnext.io/convert-country-name-to-flag-emoji-in-c-the-net-ecosystem-115f714d3ef9) to generate the corresponding country flag from a CultureInfo.

public class Region
{
    public string Emoji { get;set;}
    public RegionInfo Info { get;set;}
    public CultureInfo Culture { get;set;}
}

public static class RegionsProvider
{
    public static Region GetRegion(CultureInfo culture)
    {
        var regionInfo = new RegionInfo(culture.LCID);

        var region = new Region
        {
            Culture = culture,
            Info = regionInfo,
            Emoji = IsoCountryCodeToFlagEmoji(regionInfo.TwoLetterISORegionName)
        };
        return region;
    }

    public static string IsoCountryCodeToFlagEmoji(string countryCode) => string.Concat(countryCode.ToUpper().Select(x => char.ConvertFromUtf32(x + 0x1F1A5)));
}

<TextBlock Text="{Binding Emoji}" HorizontalAlignment="Center"/>
<TextBlock Text="{Binding Info.EnglishName}"/>
<TextBlock Text=""/>

application started

Unfortunately, in my WinUI3 application this is not displayed, but only represented by the text "us".

Can it be because of the used character set?