Preprocessing function never called

I’m very new Drupal Developer, and I would like to know why some of my preprocess function are never called.
At the beginning, I only used one single preprocess function.

// Before
function my_theme_preprocess_paragraph(array &$variables): void {
  if ($variables['paragraph']->bundle() == 'cta') {
    ...
  }
}

// Now
function my_theme_preprocess_paragraph__cta(array &$variables): void { 
  ...
}

I’d like to change the organization, so that I don’t have one big function, but several small ones. But the function I use now is never called by Drupal.

I’ve checked the machine names of my paragraphs as well as my file call, and everything seems to work correctly on this side. I’ve also cleared the cache several times using the drush cr command.

Anyone knows how fix it ?

Thanks