Proper Canonical Tag help please

Hello there.
Rank Math free. Store 15k products.
At the end of construction. At this moment it is nonindex.

Until the moment, I’m going to use RankMath pro, I would like a solution, please, to solve the part with the Canonical tag.
I’m currently testing this:


add_filter( 'rank_math/frontend/canonical', function( $canonical ) {
// change canonical URL for entire website
return $canonical;
});

add_filter( "rank_math/frontend/prev_rel_link", function( $link ) {
// change the prev rel link for entire website
$link = '<link rel="prev" href="'.get_previous_posts_page_link().'" />';
return $link;
});


However, in tests done in online tools, some say I have canonical, others don’t.

I’ve tried various things, but without ok results, like:


// create the canonical meta tag for the current page
function cano_add_canonical_link() {
global $post;
if( is_singular() ) {
echo '<link rel="canonical" href="' . get_permalink( $post->ID ) . '" />';
} else {
echo '<link rel="canonical" href="' . get_pagenum_link() . '" />';
}
}
// Add the function to the appropriate action hook
add_action( 'wp_head', 'cano_add_canonical_link' );


or


// create the canonical meta tag for the current page
function cano_add_canonical_link() {
global $post;
if( is_singular() ) {
$permalink = get_permalink( $post->ID );
} else {
$permalink = get_pagenum_link();
}
//rank math's function to insert the canonical link
if ( function_exists( 'rank_math' ) ) {
rank_math()->schema->set_data( 'canonical_url', $permalink );
if(!is_singular()){
//Get prev link
$prev_link = get_previous_posts_link();
//Get next link
$next_link = get_next_posts_link();
//If prev link exist set it as prev link rel canonical
if($prev_link) rank_math()->schema->set_data( 'prev_url', $prev_link );
//If next link exist set it as next link rel canonical
if($next_link) rank_math()->schema->set_data( 'next_url', $next_link );
}
}
}
// Add the function to the appropriate action hook
add_action( 'wp', 'cano_add_canonical_link', 20 );


Thank you