Using eval and single quotes worked for me, for example:
namespace="production" container_name="payment-service" type="event" data.event="setup_intent.setup_failed" | eval userId = 'data.event_data.data.object.metadata.user_id' | table userId
I've done that before, but don't recall if I used |eval detailsStatus = "details.status", | eval detailsStatus = 'details.status', or | rename "details.stats" as detailsStatus. Perhaps one of them will work for you.