Don't see add_filter result in the site front page

I modified the site title the 'the_title' filter. I am using ACF pro repeater, I want to achieve is that if there is content in the repeater a + will be added to the post title.

I wrote this script:

function mm_title_update( $title, $id = null ) {
    if ( ! is_admin()  ! is_null( $id ) ) {
        $post = get_post( $id );
        if (  $post-post_type == 'info' )  {
            $is_index = have_rows('index_copy', $post); //acf repeater field
   
            //check if the repeater is set
                if($is_index === false ){
                    return $title; 
                
                //die;
                }else{
                    $title .= '+';
                    return $title; 
                };
        }
    }
    
    return $title;
    
}
add_filter( 'the_title', 'mm_title_update', 1, 2 );

function mm_remove_title_filter_nav_menu( $nav_menu, $args ) {
    // we are working with menu, so remove the title filter
    remove_filter( 'the_title', 'mm_title_update', 1, 2 );
    return $nav_menu;
}
// this filter fires just before the nav menu item creation process
add_filter( 'pre_wp_nav_menu', 'mm_remove_title_filter_nav_menu', 1, 2 );

function mm_add_title_filter_non_menu( $items, $args ) {
    // we are done working with menu, so add the title filter back
    add_filter( 'the_title', 'mm_title_update', 1, 2 );
    return $items;
}
// this filter fires after nav menu item creation is done
add_filter( 'wp_nav_menu_items', 'mm_add_title_filter_non_menu', 1, 2 );

Now, the script works well on single and archive pages but it doesn't work on the site's front page.

in the front and archive pages I am using the same functionality to see the titles. the titles are called by a get_template_part from 'functions.php' file

this is the code in functions.php

 get_template_part( 'parts/title', 'loop' ); 

this is the title-loop.php file

?php
/**
 * @package hello
 */
?

span class=flex infolink
    i aria-hidden=true class=far fa-file-alt/i
    a href=?php the_permalink() ? title=?php the_title_attribute(); ? class=cat-post-title   
        ?php 
        isset()
        echo the_title(); 
        ?
    /a    
/span

I don't understand why I do not see the + sign on post loop titles on the front page. any help would be amazing tnx