4x4 Suspension Upgrade

Just changed our 2014 Mk 3 4x4 Tour de France for a 2023 Mk4 4x4 SE 2.0l diesel (multilink rear suspension). The handling on the old car was great, even at 12 years old, but the new version wallows around, and bottoms out and crashes on the uneven and potholed local roads where the old one didn't and just sailed through them. Really quite disappointed and it seems to be a common complaint, so I am after recommendations - don't want to have it too harsh, or necessarily to lower it, just want it to handle properly and not wallow and crash around! Bilstein B4 seems to be commonly recommended, but seems to be aimed more at OE replacement rather than upgrade, and am I as well also changing springs or other elements as well?