Engine damage, turbo damage, gear damage, or the cat’s broken?

Hello to all Motortalkers Have a problem with my Phaeton v10 5.0 tdi So, when I start the car the engine is running restless and loud like 1.9tdi. When gas is giving Pfeifft Turbo(But like Tudbo when no smoke comes from the exhaust? At D,R,N Ruckelt very strong which is also funny because the car bought 1 month ago and the previous owner gave me a bill of friendly that the transmission would be overhauled together (converter, O-rings, oil etc). When I switch to D the car rolls very slowly. When I give full gas it goes up to 2000 turns Totally slowly afterwards it also does not accelerate like a v10 with 313ps, maybe like a car with 80-100ps. While that gear switches not normally Rückert Extreme. If I stay longer time while acceleratoring on gas (Turbo) will probably switch off because then there is no more power. And if it is downhill it remains standing or at maximum 10kmh it’s easy to read.(I have noticed this before).