Are we able to sort by a related document's field with the REST API?

Hey! I'm looking to do a REST query like

/api/ticket/${qs.stringify(
              {
                where: {
                  user: {
                    equals: currentUser.id,
                  },
                },
                sort: 'event.startsAt',
                depth: 1, // get event data too
              },
              { addQueryPrefix: true }
            )}

But it doesn't seem like sorting by a relationship's nested field is possible. So I've gone with a frontend .sort() after querying instead

Just want to confirm that my understanding is correct here (we can't sort by a related doc's field)