I have been a professional bike mechanic for 25 years. I strongly recommend the hitch mount racks. I have and use the thule t2 pro.
https://www.thule.com/en-us/us/bike-...9034-_-1689769
I cannot tell you the number of insurance claim paperwork I have had to fill out over the years because people drive into structures with roof top racks. You want to talk about damage? Bikes = typically totaled. Rack system= typically totaled. Car roof = typically bent, dented, or otherwise not want you want.
2" hitch racks for the win. I can easily access the top hatch of my 2002 X5 when loaded.
Never ever ever go roof top. My professional .02.