How could I get Staff Member from Orders? How can I get the staff member information if my code triggered by onOrderPaid event?

Question:
How could I get information about staff member from orders in velo? I working on a unique billing integration. It would be essential to know the staff member, because we need to connect the billing account of each staff member, so that means we need to choose from 20 API codes that particular one, who will work with the customer.

Product:
Wix Studio & Bookings, and Checkout(Cart)

What are you trying to achieve:
The code start at onOrderPaid event (so after the customer paid and booked an appointment). We need billing information, thats fine, onOrderPaid event has all of that. billingAddress, lineItems has the items in order, for example if the customer book two appointments in one transaction. But this event does not have the information from the booking itself, I did not found any property about the service or the unique booking entity, so I can not get the Staff member.

What have you already tried:
Tried the onBookingConfirmed event. On that I have staff member info, but no billing informations (billing name, or company name, billing address, vat no, and also if there are more items in the order, it means more than one bookingconfirmed event) which are essential also for external billing solution. Currently we made a dumb and patched solution, and made unique service entitys for all staff member (for example “Consultation with Tim Roberts”, “Consultation with John Doe”, etc) but I hate that.

Additional information:

Try using the onOrderPaid Event as the Trigger. This ensures you have all billing and order details when the payment is completed.

Then Link Orders to Bookings. Use the orderId from the onOrderPaid event to query the Wix Bookings backend and retrieve the associated booking(s), which contain staff member information.

Once you have the booking data, extract the staff member assigned to each service and map it to their respective billing API code. Use the retrieved staff member and billing details to select the correct API code and send the data to your external billing system.

It sounds good, but I did now found the orderID in the items of booking query (Items | Velo).
Only in WixPayDetails, but it say “In case of wix-pay service, holds all payment history for a booking.”. Wix Pay is not available for us, we use official wix integration with Stripe as payment method, and sometimes manual payment as well (bank transfer). There is also an orderID in pricingPlanDetails, but this is a simple order, not pricing plan.
Did I miss something? Or are there information in the booking query array that is not listed in the description? Thank you for your time!

The resources in the wix bookings contains the details about the staff