Welcome to the forum
You have an International Ranger, which is a different truck than the North American Ranger most have here.
The Ford 3.2l is called a Duratorq engine, inline 5 cylinder with direct injection and turbo with intercooler(TDCi)
Sluggishness can be hard to define for a mechanic since it is not a specific problem that can be tested for unless you had a previous reference of "not sluggish" to go on.
Turbo wastegate could be opening to soon, fuel filters are dirty, or fuel mix has changed.
Could even be a drive train or brake issue, does it roll easily in Neutral, nothing dragging?
This is a South African 4x4 forum: 4x4 Community Forum
In English, and they drive the Ford T6 Rangers like you have so will have better experience with your model.