It has been established by those who have read through all of the witnesses. You think you understand the witness evidence by just cherry picking the witnesses whose testimony is easily available to read on the internet.
With that, you show you do not even know how to identify if someone is a witness or not!Especially in Treblinka where witnesses not only couldn't agree on the sizes of pits, the pyres, the skin colour of freshly gassed corpses, or even how the bodies burned - since some claimed blood was flammable enough to engulf a dug pit with bodies in it and burn all the corpses. In fact we have at least TWO KNOWN WITNESSES LYING SAYING BLOOD WAS FLAMMABE IN TREBLINKA. Mrs, Auerbach and Mr. Czarny. We're dealing with lunatics, here. And not one liar was ever punished in court for lying, as I already demonstrated.
There are contemporary photographs of the site to show a large area of disturbed ground at TII. That is part of the evidence that the Nazis excavated at the site.As I said before the ONLY EVIDENCE of what happened in Treblinka that Nessie has is weak eyewitness testimony, much of which violates the laws of physics and an inability to track every Jew during and after the war. Lie-witnesses and missing Jews aren't enough to established the existence of the massive pits required to hold hundreds of thousands of dead Jews in Treblinka. Hell, are we supposed to believe the Nazis were so good at dumping lime into pits in Treblinka and letting corpses rot long enough to get hard and cause wax-fat transformation barriers to prevent the top layer corpses from poisoning the water well that was in Treblinka II?
There are photographs showing human remains and with expert identification of cremated remains. That is part of the evidence people were cremated and their remains were buried there.
There are GPR and electrical resistance survey results that also show excavations of pits where witnesses stated there had been mass graves at the camp
That corroborates the witness evidence of mass graves, exhumations and reburial of the cremains.
Your arguments from incredulity, that since you do not believe the pyres would work, therefore they could not have worked, is a mere fallacy.The idea that you could pack 3000 bodies on one pyre tightly in multiple layers with no air flow around the corpses, and minimal or no wood (since we don't know whence it came and hardly any witnesses can explain it), and reduce them to smashable skeletons in 5-6 hours is stupid; it's stupid because of what past cremation experiments have taught us about how long it takes to burn one or two corpses and how much wood is necessary to keep a fire going that will be hot enough and last long enough to break open the bodies and ignite all the fat content. You can't just scream "fat content" and "wood" and "where did the Jews go then?" Nobody is denying the presence of fat content. Nobody is denying the presence or necessity of wood to burn corpses. Well that is, except for a couple of lying inmates.
That you cannot find any evidence to show what did happen instead, logically means that what is evidenced happened, despite your misgivings.