You should probably fault check better before you go throwing money away on things that you possibly don’t need.
Revving your engine in neutral sat on the driveway doesn’t prove a thing other than the fact you’ve worked out how to annoy your neighbours, so I would give that up fairly sharpish.
The best thing you can do is to plug your car into a computer and run some probably actuator tests as well as check the fault codes and check the data streams from your vehicle’s ECU.
You can run an actuator test on the VNT solenoid to ensure that it is actually operating as required, as the vacuum piping that feeds to and from the solenoid is often prone to perishing.
The actuator should give about 10mm stroke on the turbo’s control arm if functioning properly.