“I thought it would be a massive bomb.”
Jury is still out. Advanced ticket sales for opening weekend were high. Nolan has a dedicated audience. Opening weekend isn’t the problem, it’s second weekend drop off, which fewer media will report because they need this to be thought of a big success rather than a moderate one. They expect the public to be lazy and make hasty generalizations.
The Last Jedi made a tremendous amount of money and was praised by critics, but turned out to be the movie that really sank the franchise.
With Nolan's name on it it is guaranteed not to be a massive bomb - even TENET (which I have not seen) which was supposedly impenetrable plot-wise and came out during the pandemic still made almost half a billion in box office. So even if this is a total piece of cinema garbage it will do huge numbers. Enough to make a profit who knows.