Firestore V9 Sorting Field by array of objects. Being shuffled on update

Question

In my app, I have lists. these lists are categorized. Each category is stored into Firestore as a doc, along with an array of objects under that doc. The item Object contains {Name:'', Completed: ''}

When I update the "Completed" value (bool), my "onSnapshot" is triggered, but the Categories / lists are retrieved in a different order... How would I go about being able to order them? In time, the user will be able to sort, move the categories up/down themselves. So therefore I cannot hard-code a particular order that prevents the user from being able to sort those categories / lists themselves...

Here is the Firestore...

onSnapshot...

the list View

And the function that deals with the Checkbox Click