This is a good achievement by Kia. However I'm surprised that no one is pointing out that the Tesla record is from 2015 in a Model S 85D[1]. The Model S 85D had an EPA estimated range of 265 miles and the maximum charging rate was 125 kw. It would be far more interesting if this was done again with a 2021 Model Y which has a range of 330 miles and can charge at up to 250 kw, and is physically closer to the Kia EV6 in size.
It also looks like this was a pre-production model. It's very easy to change the charging params and achieve super fast charging if you sacrifice some battery health/longevity.
Also, apparently while the Kia took 7 days to do this trip, the old trip took 59 hours: https://jalopnik.com/they-drove-a-tesla-from-la-to-new-york-... . The different speed might account for some of the charging difference as well. In any case saving five hours of charging to lose over four days on the road seems like a weird trade-off.
All cars on the list should be able to do the trip in under two days. Furthermore, median predicted charging time is seven hours as well. The best results could be under six hours.
1. https://insideevs.com/news/548679/kia-ev6-charging-record-us...