You could spray directly into the Vanes with something like Wynns Turbo Cleaner. There is also a version that you add to the fuel tank. Not overly sure how the fuel version works.
I’ve had a issue recently that causes the actuator to jam, I think causing a boost issue. I believe it’s a different system on cars after 2005. But the effect I had was the same as yours, no power from cold.
https://www.volvoforums.org.uk/showthread.php?t=317202
Removing cross brace for access and then the inlet hose off the Turbo itself, which looks like it’ll be a bit of a faff, and cleaning each vane soaked with cleaner and agitating with a soft brush before starting up the engine and spraying the rest of the van though on short bursts.
I’m tempted to give the spray version a try after I’ve used the fuel one.
One thing I have done recently is give it an Italian Tune up, something I’ve never done. Locked it in 4th, rolling from 30mph and gunning it to 4K ish revs a few times. The old girl rarely sees over 2500 revs 😆