I shipped a few cars halfway across the country in the 2016 to 2019 range all open carrier for around a buck a mile. No issues with open carrier for me and that was an M5 and and LX.
When I checked shipping rates in November when mine arrived, the rates had skyrocketed. I chose to just make the drive (North Texas to Houston). Those rates are very good in my opinion and I would ship open and call it a day.