Using JsonConverter with Single Object and a List of Object

I am trying to implement a JsonConverter that will work when deserializing a single object as well as when that object is in a list. It works fine when using with a single object but not when the Json contains a array of the objects.

Here is the class:

public class APIEntity
{
    [JsonPropertyName("id")]
    public int Id { get; set; }

    [JsonPropertyName("type")]
    public string Type { get; set; }

    [JsonConverter(typeof(MyCustomClassPropertiesJsonConverter))]
    [JsonPropertyName("properties")]
    public Dictionary<string, string> Properties { get; set; }
}

Here is the JsonConverter class:

public class MyCustomClassPropertiesJsonConverter : JsonConverter<Dictionary<string,string>>
{
    public override Dictionary<string, string> Read(
            ref Utf8JsonReader reader,
            Type typeToConvert,
            JsonSerializerOptions options)
    {
        if (reader.TokenType != JsonTokenType.String)
        {
            throw new JsonException();
        }

        var dictionary = new Dictionary<string, string>();

        // Get the Json value.
        string propertiesValue = reader.GetString();

        if(string.IsNullOrEmpty(propertiesValue))
        {
            throw new JsonException();
        }

        var propertiesItems = propertiesValue.Split('|', StringSplitOptions.RemoveEmptyEntries);

        foreach (var propertyItem in propertiesItems)
        {
            var item = propertyItem.Split('=');
            dictionary.Add(item[0], item[1]);
        }

        return dictionary;
    }

    public override void Write(
            Utf8JsonWriter writer,
            Dictionary<string, string> dictionary,
            JsonSerializerOptions options)
    {
        writer.WriteStartObject();

        writer.WritePropertyName("properties");

        string propertiesValue = "";
        foreach ((string key, string value) in dictionary)
        {
            propertiesValue += $"{key}={value}|";
        }
        propertiesValue.Trim('|');
        
        writer.WriteStringValue(propertiesValue);

        writer.WriteEndObject();
    }
}

The Json looks like this for a list:

[
    {
        "id": 12706609,
        "name": "Object 1",
        "type": "Type1",
        "properties": "prop1=value1|prop2=value2"
    },
    {
        "id": 12706631,
        "name": "Object 2",
        "type": "Type1",
        "properties": "prop1=value1|prop2=value2"
    }
]

The calling code looks like this single object:

var response = await client.GetAsync(@"https://service.domain.com/getSinlge?id=12715188");
var entity = await response.Content.ReadFromJsonAsync<APIEntity>();

And like this for a list:

var response = await ient.GetAsync(@"https://service.domain.com/getLIst?id=12715188");
var entityList = await response.Content.ReadFromJsonAsync<List<APIEntity>>();

Any help would be appreciated