The first one is sort of hard to disprove because it's too vague. It may be that there are no records of such an event because it never happened, or because the records were destroyed or never written. It's one of those historically worthless unfalsifiable claims.

Like, the first thing you would want to know if you wanted to verify if this is actually true or not is what is this person's name? What lot of these stories tend to have in common is that the sources are unnamed and anonymous so you can't even look for them in documents.

The second claim is almost certainly bullshit. We actually have first hand accounts from some of the people who were closest to Stalin at the time. They would all have had to be lying for decades including long after "destalinization" when it was fashionable to slander Stalin.

The ones making these kinds of claims, mainly Trotskyites and revisionists from the Khruschev clique, were opponents of Stalin who were not directly involved in the initial meetings and could not have known except through other people, and those people never mentioned this.

Not to mention that the idea of Stalin threatening and accusing people is a very obvious attempt to evoke a Hitlerian image. That doesn't work because this is entirely out of character, by all accounts he had a very different personality to what the propaganda portraying him as this ruthless, paranoid dictator would have you believe.

If you listen to recordings of his speeches, or read the accounts of people who had conversations with him or interviewed him, they all portray him as remarkably soft spoken and intellectual. Which should come as no surprise because he was a huge nerd, he spent a lot of his time when he was not engaged in politics, reading and writing books.

Losurdo's history on Stalin goes into a lot of this (although I'm not sure about the first bit but let's be real, an impending German invasion of the USSR was already clear by the mid 1930s).

The first chapter of the book is on Red Sails and talks about Barbarossa and the Great Patriotic War. https://redsails.org/losurdo-on-the-secret-report/

The defector you mention in your first claim is Alfred Liskow, a German pioneer who harboured communist sympathies and defected mere hours before the invasion. There was simply no time to relay Liskow’s warning up the chain of command, especially in the middle of the night on the eve of the invasion.

Liskow was neither executed nor disbelieved seeing as his claims were quickly verified, however during the war he disappeared into the Soviet prison system and there is no record of his existence post late 1942.

In 1943 Stalin ordered the execution of a German defector for misinformation, although there is no evidence that indicates the executed man was Liskow.

Lastly, while a lot of the information surrounding Stalin’s dismissal of the German invasion is weird pop history misinformation, we do know that Stalin was in possession of detailed information pertaining to the German invasion prior to Barbarossa.

Primarily, Richard Sorge, a Soviet spy in Japan passed along sensitive communiques that his spy ring in Tokyo intercepted from the German embassy nearly three months before the invasion, along with a memorandum stating that he believed the Germans would invade between the months of April to May. Stalin chose not to believe Sorge’s evidence as the information reifed a potential worst case scenario that no one hoped would come true. Further assuaging Stalin’s worries was Sorge’s predicted start date coming and going without any sign of a German offensive, which lulled Stalin and the high command into a false sense of security. However, Stalin was no fool and ordered the Soviet Western Army to assume combat readiness in anticipation of a potential invasion, though many of these divisions were unable to mobilize in time and were at peacetime strength.

History would vindicate Sorge, as the Germans had originally planned to invade in late April, but were delayed by the Greek offensive which pushed Operation Barbarossa to the invasions historical start date of June 22nd.

It was the biggest military deployment in history hitherto, there is simply no way the soviets didn't know they were preparing for war against them. These rumors that Stalin didn't know or refused to acknowledge it are just bs trying to characterize him as incompetent or a nazi sympathizer.

You simply cannot move millions of troops, along with tanks and other mechanized units, with their respective supplies in secret, is just impossible. Think of the scale, it was supposed 3 millions of troops movilized for the initial invasion, that's twice the population of San Diego.