How do I reload only the table data with Laravel/Inertia/Vue

I have an orders page where, when the page loads, today's orders are shown in the table and today's date is displayed

<div>
        <h1>Showing Orders For</h1>
    </div>

    <div>
        <p>{{ selectedDates.start_date }}</p><span>TO</span>
        <p>{{ selectedDates.end_date }}</p>
    </div>

    <div>
        <p>Select New dates:</p>
        <input type="date"
               name="start_date"
               id="start_date"
               v-model="selectedDates.start_date">
        <span>TO</span>
        <input type="date"
               name="end_date"
               id="end_date"
               v-model="selectedDates.end_date">
        <PrimaryButton type="button" @click="updateDates">Update</PrimaryButton>
    </div>
    <tbody>
            <tr v-for="order in orderDetails"
                :key="order.id">
                <td>{{ order.order.order_date }}</td>
                <td>{{ order.order.order_time }}</td>
                <td>{{ order.order.customer.first_name }}</td>
                <td>{{ order.order.customer.last_name }}</td>
                <td>{{ order.order.customer.company?.company_name ?? '' }}</td>
            </tr>
    </tbody>

<script setup>
const orderDetails = ref(props.orderDetails);
const selectedDates = reactive({
    start_date: orderDetails.start_date || new Date().toISOString().substr(0, 10),
    end_date: orderDetails.end_date || new Date().toISOString().substr(0, 10),
});
function fetchOrderDetails() {
    router.get('/', selectedDates)
}
function updateDates() {
    fetchOrderDetails();
}
</script>

public function index(Request $request)
   {
       $start_date = $request->input('start_date'); 
       $end_date = $request->input('end_date'); 
       $orderDetails = OrderDetail::join('orders', 'order_details.order_id', '=', 'orders.id')
           ->with('product', 'order.customer.company')
           ->whereBetween('orders.order_date', [$start_date, $end_date])
           ->groupBy('order_details.order_id')
           ->orderBy('orders.order_date')
           ->get();
           return Inertia::render('Dashboard', [
           'orderDetails' => $orderDetails,
       ]);
   }

The orders load correctly when new dates are selected - but the dates keep going back to today's date. How do I get the dates to only reset when the user selects new dates? I've messed with partial page reloads, but haven't gotten anything to work.