there's a few factors here to consider. 1. is there proper oiling getting to the turbo, 2. is there proper coolant getting to the turbo. 3. do you know what afr's you're running at WOT. 4. what boost are you hitting and sustaining? since you're having an avcs code and turbo failures, it seems to me like the turbo isn't getting proper oil, also the avcs solenoid which is fed by the same oil feed line. if the avcs solenoid doesn't receive enough oil it will throw a 0011/0021. what people don't understand is, if a turbo blows on your turbo subaru, you have to be aware that the chra material and shrapnel can 1. end up flying out of the compressor housing and into the combustion chambers and/or 2. being drained into the oil pan and potentially recirculated throughout the engine- thus clogging any banjo filters present thus the continuance of a p0011/21 code. and when that happens, guess what, the (new)turbo loses oil from then on until the bolts are removed, inspected, and cleaned(the head banjo infront of the uppipe).
somethings fishy here, and its a coincidence that the avcs and the turbo are ill. yet they are both fed by the same oil line.