cirnogodot/Scripts/Resources/MapsDatabase.cs

using System.Linq;
using Godot;
using Godot.Collections;

namespace Cirno.Scripts.Resources;

[GlobalClass]
public partial class MapsDatabase : Resource
{
    [Export] public Array<MapResource> Maps { get; set; }

    public MapResource FindMap(StringName mapId)
    {
        return Maps.FirstOrDefault(x => x.MapId is not null && x.MapId.Equals(mapId));
    }
    
    public MapResource FindNextMap(StringName mapId)
    {
        return FindMap(FindMap(mapId).NextMap);
    }
}