There's a difference between oxidated (thickened) oil circulating in the engine, and sludge forming on components in the engine. ALL oil oxidates, even PAO and ester, and the resulting thickened particles of oil continue to circulate through the engine while degrading lubrication. This can sometimes be felt after an oil change when an engine has marginally better performance: the oxidated and thickened oil has been drained and there is less drag on the oil pump. If this thickened oil is left long enough (that is if oil change intervals are disregarded), this thickened oil can settle on parts like oil pans.
The most we can do in terms of oxidation is to minimise the percentage that forms. A good used oil analysis that measures oxidation is essential to determine if the oil is up to the task and how often it should be changed. I have noticed that most used oil analysis in the USA don't include an oxidation value which makes those UOAs useless. My Motul UOA shows 13% oxidation after about 8,000km which is excellent.
Only European-standard ACEA A3 oils can be run in Veloster turbos and API ratings don't count. As we know Rotella oil (which isn't available in Australia) suffers from foaming at high revs, and I cannot understand why anyone would run any diesel engine oil designed for low-revving diesel engines in high-revving petrol engines. Even more moronic are some who run Rotella in motorcycle engines, some of which will do 18,000rpm. My motorcycle is relatively slow-revving but it still cruises at 4,000 to 5,000rpm with a redline of 8,000rpm, and some morons would attempt to run Rotella diesel oil in this engine.
Anyone can run the wrong oil for a period of time and cause no obvious damage, but when the engine prematurely loses compression or begins to burn oil then the damage has been done. Fred runs Mobil 1 and swears by it, but if you have a turbo engine with excessive wear after 150,00km then it's too late.
Complete utter absolute BS PERIOD.
The more you post it is blatantly obvious you do a lot of "reading" and just that "reading" you have no real world exp with High HP Turbo applications. Never have and no nothing about what keeps an engine together. Hint: Your engine is not going to magically last longer than someone else running a different oil. If you think this there is no hope for you. Sell your car and get a bicycle
Keep on reading all your useless theories while the people in the know keep making power