JWFacts website as tons of stuff, including WT "literature" references.
Here is the section on "Generation": https://jwfacts.com/watchtower/generation.php
One of my favorite arguments:
Even the masthead of the Awake! changed with this new teaching. Until 1995, it said: "This magazine builds confidence in the Creator's promise of a peaceful and secure new world before the generation that saw the events of 1914 pass away."
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This was changed in November 1995 to: "This magazine builds confidence in the Creator's promise of a peaceful and secure new world that is about to replace the present wicked, lawless system of things."
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The Watchtower published, 24 times a year, for literally decades, that the "creator's promise..." would occur "...before the generation that saw the events of 1914 passes away."
Obviously anyone who "saw the events of 1914" would have to be at least 110 years old today. There are estimated to be 150 - 600 such persons alive on earth today. Another couple of years and the number will be in single digits, or all will be dead.
Ask your debating opponent, "The magazine said Jehovah promised a new world before the generation that saw the events of 1914 passed away. The new world is not here. So did Jehovah break his promise?" Of course they have to answer "No".
Follow up with "So, Jehovah didn't make such a promise. What should Jehovah do to an organization that printed, literally hundreds of times across many decades, words that made it look like the creator broke his promise? They spoke lies and attributed them to Jehovah. That is the definition of a false prophet. What should happen to a false prophet?"