Issue with nested freezed class

[drinikol]

Good Day! New to riverpod and freezed, I encountered this problem when pushing to firestore, I have freezed classes that are nested to each other, all have the @JsonSerializable(explicitToJson: true) but I encounter this problem, when trying to upload to firestore. What am I missing? to make this work. Thank you!

[cloud_firestore/invalid-argument] Function setDoc() called with invalid data. Unsupported field value: a custom _$36ProductDimensionImpl object (found in document orders/-O6CM27hmACSNq4q8tPs/cart-items/-O6CM27h1OVrA1phAHhm)

part "main_panel.freezed.dart";
part "main_panel.g.dart";

//
///The CART ITEM OR MAIN PANEL
@freezed
class MainPanel with _$MainPanel {
  @JsonSerializable(explicitToJson: true)
  MainPanel._();
  factory MainPanel({
    String? id,
    @Default(1) int quantity,
    FProduct? product,
    Shape? shape,
    List<String>? uploadedImages,
    List<SubPanel>? subPanels,
    int? created,
    int? modified,
  }) = _MainPanel;

  double computeSubPanelsTotalAmount() {
    double total = 0.0;
    if (subPanels == null || subPanels!.isEmpty) {
      return total;
    }
    for (SubPanel subPanel in subPanels!) {
      total += subPanel.getTotalAmount();
    }
    return total * quantity;
  }

  factory MainPanel.fromJson(Map<String, dynamic> json) =>
      _$MainPanelFromJson(json);
}

part "sub_panel.freezed.dart";
part "sub_panel.g.dart";

@unfreezed
class SubPanel with _$SubPanel {
  @JsonSerializable(explicitToJson: true)
  SubPanel._();
  factory SubPanel({
    String? id,
    ProductDimension? dimension,
    ProductColor? fabricColor,
    ProductColor? frameColor,
    String? motorType,
    List<AddOn>? accessories,
    @protected double? amount,
  }) = _SubPanel;

  factory SubPanel.fromJson(Map<String, dynamic> json) =>
      _$SubPanelFromJson(json);

  double getTotalAmount() {
    double newAmount = 0.0;
    if (amount != null) {
      newAmount = amount!;
    }
    return newAmount;
  } 

targets:
  $default:
    builders:
      json_serializable:
        options:
          any_map: true
          explicit_to_json: true
    ```