Don't know what is different in your 23 vs my 24 PHEV, but the Kia adaptive cruise has always seemed not quite as good as even the last generation of Toyota adaptive cruise (on which I've driven tens of thousands of km on sometime dodgy roads and it has been rock solid and never wanted to accelerate or decelerate excessively except for emergency braking or mis-steer with the lane assist), although I am starting to trust the Kia system more, but it does seem to have more quirks and it doesn't seem to be able to recognize road markings as consistently as Toyota, so the lane assist tends to come on and off frequently (it does work fantastically when in Highway Drive Assist mode though; it's just the normal non-highway mode that is sometimes more stress-inducing than reducing).. I think one thing that would make me feel a bit more comfortable is a "release bing" sound like Toyota can do whenever the ADAS turns off and wants you to take over. The Kia has no audio setting and just stops working whenever..
In any case, on the Kia, 95% of the time it works well, but again, there are times, generally when I manually slow for traffic and then reactivate the cruise with a clear lane ahead, or as the OP noted that a car cuts across your lane and then out, again leaving the front clear, that it seems to think it needs to accelerate hard (and maybe this is not really just an artifact of how quickly the electric motor can modulate the vehicle speed, sort of like the hydraulic cylinders on flight simulators and Disney rides can simulate the feel of motion and G-forces) and if it catches up to traffic before it reaches the set speed limit, it doesn't seem to want to slow until you're right up to the car in front, and then it aggressively brakes late. Now it always stops on the few occasions that I have nervously hovered my foot over the brake and let it do its thing just to see where it would stop, but it stops a lot closer to the lead vehicle than I would ever normally be comfortable with (about 2 feet). In "normal" operation, when this anomalous acceleration is not triggered, the car works as expected, gradually slowing and stopping a reasonable distance from the car in front and you never feel the sense of hard acceleration or braking.. I've tried all the settings to try to fix this and all the settings do is to change the behaviour in "normal" operation, but they don't seem to affect this anomalous condition...
Again, don't know what the difference is between your 23 and my 24 is, or whether road conditions and driving style of myself or others in my area contribute to the behaviour of the ADAS, or whether the feeling is just due to the way the electric motors work, but I can attest that there are situations when it does feel like it is accelerating very hard (again, more so than the settings say to do: I've currently got my settings to fastest reaction time, but slowest acceleration) and nothing really explains why on these occasions,it wants to stop so close to the leading vehicle...