I have a 2014 Honda and it does not have direct injection, my 19 Highlander did not have direct injection neither did my 2017 Tundra. My POS 2016 ford f150 had DI and they were known to have carbon issues. It was bought back by the factory because of issues DI caused (like low vacuum) They went to DI and MPI in 2017 to fix those problems.
I'm not sure what kind of Honda you have so I can't speak to that. If you've got a 2019 Highlander with a V6 then it is direct injection, that's all they made that year. The 5.7L V8 in the Tundra is not a direct injection engine but it came out in 2007 which is why I said anything designed within the last 15 years or so. Yours might have been made in 2017 but it's an old, but reliable engine. I have a 2016 Tundra.
The early direct injection engines had carbon buildup issues on the intake valves. It was discovered that since the fuel was directly injected into the cylinder the valves weren't benefitting from the fuel cleaning them like in a normal engine. That issue was solved by using a dual mode injection which injects a small amount of fuel into the manifold (port injection) with the main charge being direct injected. This small amount of intake fuel is enough to keep the valves clean which solved the carbon problem. That's what Ford did that you described. The problem was not unique to Hyundai and to my knowledge nobody makes a DI engine that does not have the dual mode system today, Hyundai's webpage specifically describes their dual mode system. I think that when Toyota started using direct injection they always used the dual mode system so they never had the problem. Early on some of the luxury car makers like BMW and Audi went in heavy on direct injection before the problems were understood and they had a lot of problems with carbon buildup. So yes, they had problems when direct injection first came out but they've been solved now. While there may be a few older designed engines still being produced that don't have direct injection, almost all new gas engines are going to have it, it's good for about a 15% fuel economy boost because it lets them run a higher compression ratio.
I've never had a Hyundai or Kia, I'm a Toyota guy. I know several people that have owned them and all have had good service out of them. I've never heard of anyone with premature engine problems from them. I'd certainly trust them over any domestic manufacturer.
