Paradox, mine is clunky until warm so I know where you're coming from - but surely r5 would have noticed this a long time ago if this was the issue. To me it sounds like it is a recent issue.
OEM+ If you experienced the same issues and managed to resolve it, then that sounds promising. However, the P0441 code is very common and I haven't heard of it causing this issue before. Could be...
Maybe try both a DSG adaption and throttle body adaption. Maybe even clean the throttle body whilst you have the rest of the front end off? They are free exercises that can rule out potential causes