Fetch a single post from a list of posts using the REST API

To help you, we need to know what the “my_post” action looks like in your code. Somewhere in your code, there must be an add_route with “my_post.” Can you show us what it looks like?

add_route('my_post', array(
    ...
));

By default, you can filter your posts in WordPress using the following route: ?rest_route=/wp/v2/posts/${POST_ID}.