Create a custom page template that does the following:
Get the current user’s ID with get_current_user_id().
Use a new WP_Query object to get all posts authored by the current user ID, ordered by category.
Run the standard “Loop” on the returned posts.
In order to know which category header to output, and when to output it, check the categories of each post with wp_get_post_categories().
When the loop is done use wp_reset_postdata().
There is one complication preventing this from being fairly straight forward. You can’t use WP_Query alone to order by category. To order by category, hook into the filters ‘posts_join_paged’ and ‘posts_orderby’ and alter the query parameters to get the results ordered by category. This part of the code would go in your theme’s (or better yet, your child theme’s) functions.php file.
Once all that is taken care of, add a new page and specify to use your custom template. You only need to assign a title to define the permalink used to access the page. You do not need any content unless you’ve set up the template to use content.
