Firebase firestore timestamp query returns no documents

I'm trying to retrieve some documents from a collection based on the timestamp falling on a specific day. I know I have documents in my collection that fall between these time stamps but it keeps returning nothing. If I remove the 'startTime' query parameters then I am able to retrieve documents.

Am I querying the timestamps incorrectly?

StartTime stored as timestamp in firestore

// Get bookings from firestore
firestore
    .collection('bookings')
    .where('studio.ID', '==', 'kM8p1jSenI4M0Mr1PzBo') /// Works fine with this query 
    .where('startTime', '>=', dayjs(date).valueOf())  /// 1631415616880
    .where('startTime', '<', dayjs(date).add(1, 'day').valueOf()) /// 1631502016880
    .get()
    .then((querySnapshot) => {
        querySnapshot.forEach((doc) => {

            console.table(doc.data());
            setBookings(doc.data());
        });

Also tried query as a date object:

const [date, setDate] = useState(new Date(new Date().setHours(0, 0, 0, 0))); //setting initial state to current day midnight
    const [step, setStep] = useState(0); // Count the days ahead the user is trying to book.
    const [alert, setAlert] = useState(false); // Alert when trying to exceed booking window.
    const [bookings, setBookings] = useState({});

    const bookingWindowAllowed = 7; // Used to limit the forward bookings (evaluated vs state.step)

    useEffect(() => {
        setLoading(true);
        console.log('Set date is:', date);

        const setDate = new Date(dayjs(date).valueOf()); //Date object for today
        const futureDate = new Date(dayjs(date).add(1, 'day').valueOf()); //Date object for tomorrow
        console.log('Set date is:', setDate);
        console.log('Future date is:', futureDate);

        // Get bookings from firestore
        firestore
            .collection('bookings')
            .where('studio.ID', '==', 'kM8p1jSenI4M0Mr1PzBo') /// Works fine with this query
            .where('startTime', '>=', setDate) /// 1631415616880
            .where('startTime', '<', futureDate) /// 1631502016880
            .get()
            .then((querySnapshot) => {
                querySnapshot.forEach((doc) => {
                    console.table(doc.data());
                    setBookings(doc.data());
                });
                setLoading(false);
            })
            .catch((error) => {
                console.log('Error getting documents: ', error);
                setLoading(false);
            });
    }, [date]);