Flutter: Implementing undo - keeping object copy vs keeping references to anonymous functions

Question

I'm developing a sort of editor in Flutter and it should have an undo/redo functionality. In my editor, my the different operations done by the user are done on a Design object. I'm using freezed (https://pub.dev/packages/freezed) for building my object model. Here's what it looks like:

@freezed
class Design with _$Design {
  const factory Design({
    required int id,
    required String name,
    required DiagramOrientation orientation,
    @ColorConverter() Color? backgroundColor,
    required String backgroundImage,
    required String logo,
    required List<DesignArea>? areas
  }) = _Design;

  factory Design.fromJson(Map<String, Object?> json)
      => _$DesignFromJson(json);
}

To implement undo/redo functionality I have 2 options that I have thought of.

1. Create some kind of class that will hold an "operation":

class DesignOperation {
    final Design design;
    final String name;

    const DesignOperation(required this.design, required this.name);
}

On each operation create this class with the name of the operation (for operation history displaying purposes) and insert a copy of the object into a list (managing the max number of allowed operations, removing operations when inserting new ones after undo, etc...). Undo/redo would be just to update the object to the correct place in the list.

2. Use a library I found for undo/redo - https://pub.dev/packages/undo. Looking at this library I would need to change my Design model to be @unfreezed, and when calling add I pass 2 anonymous functions (which hold a reference to the variables in my code and basically having to be working with closures).

I'm wondering, development wise, performance and memory what would be the better approach - copies of my object or keeping anonymous functions with references to my object properties.