C70 D4204T noisy cold start

[MichaelP62]

I have a problem with my C70 diesel engine (EUR5, built 6/2010, MPS6 transmission, 2011 facelift version). The car has done 146.000 km or 90.700 mi. When starting with cold engine, the car is very noisy inside on idle and when accelerating from stop. The noise is not heard outside and is not a faulty exhaust. The idle is also a bit rough/uneven in my opinion. The engine shakes on idle, even the steering wheel shakes a bit. This has gone worse after use of fuel additive, which I added upon fuel filter change.
The following has been done:
-Change of all three engine mounts
-checked injectors for outside leaks
-fuel filter changed (Volvo original). + added fuel system cleaner to filter house and tank.
-injector leak off test. 5 min on idle —> 45, 50, 45 and 55 ml leak off from innjectors 1-4, respectively (I assume this is within specs, which I don’t actually have for these injectors)
-all 4 injectors sound and feel normal (listening with screwdriver and feeling with finger how they activate)
-cleaned the throttle box, MAF and temp. sensors. Very little oil and soot. Nothing I would mention
There are no fault codes, confirmed at Volvo dealer garage.

What would you do next? EGR? Fuel system (pump, injectors, pressure valve)?
Should I take it to a shop for checking the injectors with VIDA? Or, worst case, you think it´s normal and I´m too fuzzy… Iwould love to have a premium car, not a tractor.