Cinematic Confusion

The PEPLUM genre gets little respect, with a constant set of confusing and contradicting information on films from the genre including titles. As proof of this here are 4 examples of titles which should be in the plural are misidentified in the singular (with one example being the opposite). One missing letter "S" in the title makes a big difference. So here are screenshots of the titles as seen during the film vs information on the web.

Even if the artwork says GLADIATORS Amazon is selling it under the wrong title.

Is the challenge coming from one gladiator or a bunch of them?

This is the title that made me realize this problem with PEPLUM film titles and the plural

As opposed to the previous 3, the word PIRATE in this title should be in the singular but IMDb has it in the plural.