Welcome to the forum.
I have a DCT with no issues @ 67k miles. It is a stick-gearbox with a computer-driven dual-clutch; not a slushbox automatic. There are others here who have more experience than I do on this and I suspect they will chime in. My DCT, I drive it like a stick. I am not hesitant with the throttle. A slushbox deals with that a bit better than the DCT. The DCT needs me to be committal to the throttle. The throttle is not an on/off switch, but a DCT doesn't seem to like the mess around. The gearbox is pre-selecting the gear based on what it senses is going on; so if you get going in 1 first, the gearbox has already pre-selected 2nd in anticipation of continued acceleration...then third, and so on. Hence the dual-clutch...one clutch for 1st gear, second clutch engages 2nd, then first clutch engages 3rd gear, and so on. SO you can, sort of mess up its understanding by being hesitant with either throttle or brake. The jerky feeling may be the gearbox or how you drive it. If you are braking and turning and coasting (no throttle), the gearbox may not know whether to go up or down a gear. Best to drive it like old-school race cars. Get all your braking done in a straight line. Back on the throttle while cornering. A DCT doesn't seem to understand trail-braking very well; it confuses the computer trying to figure out if you are stopping (trying to downshift next) or getting ready to accelerate (trying to upshift). On the other hand, as I said earlier, the gearbox does have some issues. What year is your car? I see your profile says it's a 2013.
The rattling may not be the gearbox. Could be a CV joint or a motor mount or a bad exhaust hangar. How many miles on the car? Tell us more about the rattling. Is it consistent...same conditions all the time? Have you changed anything lately that now could be loose? Because you hear the rattling when you turn, I immediately go to CV joints, but more detail would help.
