All golds on Nordschleife CE with those buttons on DS4 no less is quite impressive. Maybe try L2/R2 (I hear they suck on the DS4 though) or else right stick (up/down) for throttle and break. Should make you faster after a short getting used to.
Personally I finally managed to get my hands on this bad boy to complete all cafe menus. Resulting 6 star ticket netted 500k.