None of that is true.
1) After a decent for the situation opening, WW84 crashed and burned last weekend, down by 70%. It's grand total is now $28 mil. Whether that's because everyone who is willing to go to a theatre in the middle of a pandemic went to see it when it opened or the bad word of mouth and the bad critical reviews caused the drop is unknown.
The only place it is doing well is Australia.
2). "Dune will make half WW84 makes" is a nonsense statement. No, it's not as well known as wonder woman, but it's still the best selling sci fi novel in history, has been topping the Amazon charts again since the trailer dropped, stars the hottest cast in Hollywood today, is directed by one of the hottest directors (who considers it the best film he has ever made), and, as planned, was supposed to be the start of its own kind of cinematic universe with TV shows and films. The people making it obviously expected this to be a billionish dollar film (and it is called such in many of the letters/articles written by insiders since the WB/HBOMax announcement) . It very well may bomb covid or no covid. It's a risk. But while your and others personal expectations are that it would never be financially successful, the people making it obviously think otherwise. Plus, October will not be Dec 2020. What it will be no one knows, but no one thinks it will be as bad as the current situation. Most places are hopeful the vaccines will be fully distributed by then - although, again, anything can happen.
3). WB invested only 1/4 of the budget for Dune. That's why they want it on HBOMax. They get paid twice for every rental on HBOmax. They would make their money on it. That's why it's set to go there. It's everyone else BUT WB who loses money on HBO max - the people who actually paid for and made the film. WB doesn't want theatrical. They aren't re-evaluating ROI on Dune based on WW84. Wonder Woman is part of an in house money printing machine. Dune is a distribution deal. They're completely different financial situation for WB.