modifying query in pre_get_posts hook doesn't take effect

Hi,

I’m creating a category template where I’m wanting to tailor the query a bit before they are displayed. I’m trying to use the pre_get_posts hook, but no matter what I do to the query here, no changes take effect.

Is the theme overriding what I’m doing in pre_get_posts after my code? How can I modify the query?

I should mention that my category template is identical (copied and pasted) from the default “category.php” file that comes with the theme.

At least you can answer this question? :

Is the theme overriding (or modifying the query) after my own pre_get_posts() hook, regardless of the hook priority? The code for this is placed in the theme’s functions.php file.