Author ID insted authorname

First, go to a users admin page

Admin Dashboard>Users>All users>Hover over the # of posts field for that user>Look below in your browser for the user ID # contained in the string. Then, per this example:

//sitename.com/?author=ID

I don’t like to have that information available so I redirect in .htaccess anyone using such a url per this example:

<IfModule mod_rewrite.c>
RewriteRule  ^author/(.*)$  https://sitename.com  [R,L]
</IfModule>

i dont wanna use htaccess. i know that this can be done with add_action, but i dunno how

Please describe in greater detail what you are attempting to achieve.

And see these:

https://codex.www.ads-software.com/Plugin_API#Hook_to_WordPress

https://codex.www.ads-software.com/Function_Reference/get_current_user_id

I know about all functions but i dunno how to write a filter.

again:
I have link to the author page https://sitename.ru/author/akapellos
Now i wanna rewrite this url to show users ID, not username.
https://sitename/author/50 (user_nicename=ID => akapellos=50)

i searched this

$alt_user_nicename = $user_nicename . "-$suffix";
$user_nicename_check = $wpdb->get_var(
$wpdb->prepare("SELECT ID FROM $wpdb->users
WHERE user_nicename = %s AND user_login != %s LIMIT 1" ,
$user_nicename, $user_login));

but i cant find any vars that includes user_nicename

OMG! I found it!
In author-template.php

function the_author_posts_link
$authordata->ID

and

function get_author_posts_url
$user->ID