ViewModel versus a ClassManager

Question

Whilst I've been programming for years, I am learning how to use the Model-View-ViewModel Archictecture and how to integrate it and other Patterns.

I have a Class Car. I have a Class CarManager, that maintains a list of Cars. It also contains methods to handle actions on the List, such as saving to XML for example. Currently I move/reference the list of Cars in my app using an instance of my CarManager Class.

I have seen examples like this https://learn.microsoft.com/en-us/answers/questions/1468715/how-can-i-update-a-datagrid-from-another-window (thanks to Hui Liu-MSFT for the help!) where the ViewModel stores a List of Cars directly.

Should I have a reference in the ViewModel to my instance of my CarManager Class containing an observable collection of Cars, or should I just use a seperate Observable Collection of Cars? It seems a bit messy to create another list.

If I use a reference to a CarManager Instance, how would the DataBinding Change?

ie. instead of this in the CarViewModel

        public ObservableCollection<Car> Cars { get; set; } = new ObservableCollection<Car>();

have

 public CarManager  CarManager{get; set;} = new CarManager;

(where Car Manager actually has the ObservableCollection)

Many thanks!