First I would establish actuator movement. The failure of the actuator to move properly is the leading cause of VW turbo failures.
With a vacuum pump, such as a Mighty-Vac, or the Harbor Freight clone, draw 30" of vacuum. You can access the line for the turbo on top at the solenoid on the firewall.
30" should sustain for more than 10 seconds to a vacuum of 25 or more. If not, you have a leaky diaphragm, hose or connections.
Next, either looking from on top, or from under the car (easier to spot under) verify that the actuator moves at least 5/8". If it does, then the actuator itself is working OK.
If you have gotten this far, and the actuator does not move at least 1/2" you have either an actuator problem, or sticky vanes, or both. The most common cause is sticky vanes.
If the actuator is moving smoothly, and the actuator is holding vacuum, then your problem may be in the control circuit (solenoid and forward) or in the turbo. Usually a total actuator failure causes copious white smoke, from unburned fuel, due to lack of boost (and airflow).
Completely answering all possible scenarios is beyond the scope of this answer, but I will tell you that commonly there is carbon buildup in the vanes which limits their motion. Mechanical means (disassembly and cleaning) work well, but as you have noted are time consuming. A variant mechanical method, which a friend has done many times, is to move the linkage back and forth vigorously, with the actuator disconnected. This usually results in improved, but not perfect operation. A chemical approach involves a caustic agent, such as spray oven cleaner, being delivered to the turbo, allowing the carbon buildups to soften. Some have used this method, but I have not, although it is tempting.
Unfortunately I have not found a good guide to diagnosing and resolving VW turbo issues. However, there are several forums where people have documented their experiences and some experienced people share their knowledge.