Engine speed is too high and power is missing

Hello to everyone. I’ve already written the vileicht the turbo is broken but jetzt I found something new rasu. And I noticed this morning that if you drive in 5 gears I can just 150KM/H. Now I wanted to ask if the normal is that you drive 150 KM/H at a speed of 4,000 revolutions and the whole in 5 gears. And then I still noticed if I drive in 3 gears the MOtor should still rule normally at 4,000 revolutions nevertheless or not. goes the even further up 6,000 and even more hope me the who can help further whether this is normal or not. Thanks already to all de get in touch here.