I have a solution for you. Unfortunately, you are correct in saying that there aren't any manufacturers that have created a hitch specifically for your 2019 Genesis G70.
With that being said, if you are worried about the amount of surface area that makes contact with the vehicle with a trunk-mounted rack, I recommend a roof-rack system. In particular, I recommend the SeaSucker Monkey Bars # 298-SX6000B. Not only do the Monkey Bars have the easiest install/uninstall process, they also... view full answer...
The trunk mount bike rack options for a 2020 Genesis G70 are all hanging style racks and while these will technically get the job done, since you have carbon fiber bikes you want to avoid using a bike rack that will be in contact with your bike frames.
Normally I would say go with a trailer hitch and a hitch mount bike rack because they are more cost-effective and easier to use, but there are no trailer hitches that fit your 2020 Genesis G70 so you'll want to go with a roof rack and a... view full answer...