Edit the excerpt length?

In your theme’s functions.php file add this:

function custom_excerpt_length( $length ) {
    return 40;
}
add_filter( 'excerpt_length', 'custom_excerpt_length', 999 );

Changing return value changes the excerpt length.
Please let me know if this answers your question. Thank you.l

public_html/wp-content/themes/plum/functions.php

This has no effect for me. Have you tested that?

Hello @danste

Can you please share the URL of your site so that we can take a look at the site and resolve it for you.

Divjot