handing reorder update with fetchRequest (core data)???

ould the below be the most appropriate way to handle updating the orderNum of items in a List when the manual order is stored in core data (as the orderNum field).

Specifically I note when I try to cycle through my fetchedResults list after I have deleted an item, that item is in fact still there. So what I'm doing is doing a core data save, and then after this updating the orderNum and then resaving. OK approach?

Key code sections:

    @Environment(\.managedObjectContext) var context
    @FetchRequest(fetchRequest: GCList.allListFetchRequest()) var gcLists: FetchedResults


    private func save() {
        // Save
        do {
            try self.context.save()
        } catch let e as NSError {
            print("ERROR : \(e.description)")
        }
    }

    private func deleteList(at offsets: IndexSet) {
        // Remove Items
        for index in offsets {
            let list = self.gcLists[index]
            self.context.delete(list)
        }
        self.save()

        // Redo orderNum  *** NEED TO DO ANOTHER UPDATE/RESAVE LIKE THIS ***
        var i = 0
        self.gcLists.forEach { gcItem in
            gcItem.orderNum = Int64(i)
            i += 1
        }
        self.save()
    }