How to solve 404 error on page navigation without category in WordPress?

Question

htaccess

Good day!
For pagination I use the standard paginate_links() function Permalinks say
: /%category%/%postname%/
htaccess has 301 the first redirect from the standard site.ru/category/cat_name to site.ru/cat_name Post
output cycle:

<?php while (have_posts()) : the_post(); ?>
...
<?php endwhile; ?>

When you go to the second and subsequent pages of navigation - error 404.
I understand that this is somehow connected with the redirect, but I don’t want to remove it (I like just such a CNC).
Please help me, how to solve this problem?