Retrieve the category of a service

Hi, I need to retrieve the category of a service after a booking has been confirmed. The wixBookings_onBookingConfirmed ( event ) will only return the service ID. I thought it might be enough using a good old query to the Services collection, but this field isn’t included on the returned item.
I tried using .includes(“category”) but apparently it is not some sort of hidden refference field either.
I looked into the full API Library and it seems that there are no requests that would return a service’s category.
I saw that some other users experience the same issue for already quite some years, and it seems that it is not yet fixed. I therefore believe that there is a solution. Any idea ?

Thanks !