You've obviously broken something - Not sure what you are expecting when running flat out - things get hot and go bang.
Whether it is the turbo, or something engine internal related remains to be seen, further investigation i.e. stripping down will be needed to resolve.
I'd be pulling the downpipe and checking the hotside of the turbo for play and evidence of oil leakage, I'd be dropping a boost pipe and checking if it is full of oil to see if originating from the cold side, I'd pull the intake and check for evidence of oil originating from the PCV feed in to the turbo housing, along with the PCV on the front of the engine going in to the inlet manifold to understand where the oil is originating from. Don't fit a silly PCV delete - if the current one is working correctly (5 seconds to check) then leave it be
I will check all that later.. how can I check if my PCV is still working? There are no codes for it on VAGCOM but maybe it is faulty?
Remove the oil cap with the engine running. If the diaphragm has popped, it will create way too much vaccum under the cam cover making it very hard to remove the oil cap. This can actually cause your white smoke issue in extreme cases. You should only feel a slight bit of vacuum when removing the cap.
Might be worth replacing it anyway as it's not an expensive or difficult part to replace.