WordPress pagination returns the same posts

You must change

$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;

To the following :

 $paged = (get_query_var('page')) ? get_query_var('page') : 1;

There is a difference in page and paged for a static front page, You may find your Answer here : https://developer.wordpress.org/reference/classes/wp_query/#pagination-parameters

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