I would love to see the Hyundai Rally Car, TCR Car, and the 2022 Hyundai Elantra N in the game since Hyundai has more than just the Veloster N now.
In regards to the Elantra N, Adro makes some cool wings/body kits for it. That car and body kit would be awesome to see in the game as well. I also have not seen the Tiburon mentioned at all.
Hyundai has also released some of their concept cars recently. These would make a great addition to FH5 as well.
The Genesis cars would also be amazing to see in FH5 and the new FM games. There are some cool body kits out there for the Hyundai Genesis, and the brand Genesis also has some great cars like the G70 and G90 are great cars.