Hi.....welcome to the Forum
If it has a turbocharged engine then sometimes the variable vanes become gummed up with carbon through lack of revs to keep everything clean and moving.
You can buy a cleaner to run through the turbo to clean it up and a good blast helps to shift the carbon.
Also, it could be an Air Mass Meter (MAF sensor) fault which is causing the loss of power.
https://autoevoke.com/index.php?/news/forums/guide-to-maf-sensors-r134/
A scan of the fault code memory should reveal some more information as to what is going on