❔ Is the functionality of my code in the right place

namespace Stand.Libraries.Website.Sitemaps.Domain.ValueObjects;

public class SitemapPage : IEquatable<SitemapPage>
{
    public SitemapPage(IReadOnlyCollection<Page> pages)
    {
        Pages = pages?.ToList() ?? throw new ArgumentNullException(nameof(pages));
    }

    public List<Page> Pages { get; }

    public bool Equals(SitemapPage other)
    {
        if (ReferenceEquals(null, other)) return false;
        if (ReferenceEquals(this, other)) return true;
        return Pages.SequenceEqual(other.Pages);
    }

    public override bool Equals(object obj)
    {
        return Equals(obj as SitemapPage);
    }

    public override int GetHashCode()
    {
        return Pages.GetHashCode();
    }

    public override string ToString()
    {
        XNamespace xmlns = "http://www.sitemaps.org/schemas/sitemap/0.9";
        XNamespace xhtml = "http://www.w3.org/1999/xhtml";

        var urlElements = Pages.Select(page =>
        {
            var pageElements = new List<XElement>
        {
            new XElement(xmlns + "loc", page.Url)
        };

            if (page.LastModified.HasValue)
                pageElements.Add(new XElement(xmlns + "lastmod", page.LastModified.Value.ToString("yyyy-MM-ddTHH:mm:ss+00:00")));

            if (page.ChangeFrequency.HasValue)
                pageElements.Add(new XElement(xmlns + "changefreq", page.ChangeFrequency.Value.ToString().ToLowerInvariant()));

            if (page.Priority.HasValue)
                pageElements.Add(new XElement(xmlns + "priority", page.Priority.Value.ToString(CultureInfo.InvariantCulture)));

            if (page.Cultures?.Any() == true)
            {
                foreach (var culture in page.Cultures)
                {
                    pageElements.Add(new XElement(xhtml + "link",
                        new XAttribute(XNamespace.Xmlns + "xhtml", xhtml),
                        new XAttribute("rel", "alternate"),
                        new XAttribute("hreflang", culture.Name),
                        new XAttribute("href", culture.Url)));
                }
            }

            return new XElement(xmlns + "url", pageElements);
        });

        return new XDocument(
            new XDeclaration("1.0", "UTF-8", null),
            new XElement(xmlns + "urlset", urlElements)
        ).ToString();
    }
}

namespace Stand.Libraries.Website.Sitemaps.Domain.ValueObjects;

public class SitemapPage : IEquatable<SitemapPage>
{
    public SitemapPage(IReadOnlyCollection<Page> pages)
    {
        Pages = pages?.ToList() ?? throw new ArgumentNullException(nameof(pages));
    }

    public List<Page> Pages { get; }

    public bool Equals(SitemapPage other)
    {
        if (ReferenceEquals(null, other)) return false;
        if (ReferenceEquals(this, other)) return true;
        return Pages.SequenceEqual(other.Pages);
    }

    public override bool Equals(object obj)
    {
        return Equals(obj as SitemapPage);
    }

    public override int GetHashCode()
    {
        return Pages.GetHashCode();
    }

    public override string ToString()
    {
        XNamespace xmlns = "http://www.sitemaps.org/schemas/sitemap/0.9";
        XNamespace xhtml = "http://www.w3.org/1999/xhtml";

        var urlElements = Pages.Select(page =>
        {
            var pageElements = new List<XElement>
        {
            new XElement(xmlns + "loc", page.Url)
        };

            if (page.LastModified.HasValue)
                pageElements.Add(new XElement(xmlns + "lastmod", page.LastModified.Value.ToString("yyyy-MM-ddTHH:mm:ss+00:00")));

            if (page.ChangeFrequency.HasValue)
                pageElements.Add(new XElement(xmlns + "changefreq", page.ChangeFrequency.Value.ToString().ToLowerInvariant()));

            if (page.Priority.HasValue)
                pageElements.Add(new XElement(xmlns + "priority", page.Priority.Value.ToString(CultureInfo.InvariantCulture)));

            if (page.Cultures?.Any() == true)
            {
                foreach (var culture in page.Cultures)
                {
                    pageElements.Add(new XElement(xhtml + "link",
                        new XAttribute(XNamespace.Xmlns + "xhtml", xhtml),
                        new XAttribute("rel", "alternate"),
                        new XAttribute("hreflang", culture.Name),
                        new XAttribute("href", culture.Url)));
                }
            }

            return new XElement(xmlns + "url", pageElements);
        });

        return new XDocument(
            new XDeclaration("1.0", "UTF-8", null),
            new XElement(xmlns + "urlset", urlElements)
        ).ToString();
    }
}

namespace Stand.Libraries.Website.Sitemaps.Application.Services;

public class MapService : IMapService
{
    readonly IEnumerable<ISitemap> _sitemaps;

    public MapService(IEnumerable<ISitemap> sitemaps)
        => _sitemaps = sitemaps;

    public IReadOnlyCollection<Map> GetMaps() 
        => _sitemaps
        .Select(map => new Map(map.Name))
        .ToList();

    public SitemapIndex GetSitemapIndex()
    {
        var maps = _sitemaps
            .Select(map => new Map(map.Name))
            .ToList();

        return new SitemapIndex(maps);
    }
}

namespace Stand.Libraries.Website.Sitemaps.Application.Services;

public class MapService : IMapService
{
    readonly IEnumerable<ISitemap> _sitemaps;

    public MapService(IEnumerable<ISitemap> sitemaps)
        => _sitemaps = sitemaps;

    public IReadOnlyCollection<Map> GetMaps() 
        => _sitemaps
        .Select(map => new Map(map.Name))
        .ToList();

    public SitemapIndex GetSitemapIndex()
    {
        var maps = _sitemaps
            .Select(map => new Map(map.Name))
            .ToList();

        return new SitemapIndex(maps);
    }
}