To make the admin sidebar menu always be collapsed, try adding the following code in the functions.php
file of your child theme, or add it in your site using a plugin like Code Snippets, or Add Actions and Filters.
global $user_ID;
$user_fold = get_user_meta( $user_ID, 'wp_user-settings', true );
$exp_array = explode( "&", $user_fold );
$search_array = array_search( "mfold=o", $exp_array );
if ( $search_array ) {
$exp_array[ $search_array ] = "mfold=f";
$exp_array = implode( "&", $exp_array );
update_user_meta( $user_ID, 'wp_user-settings', $exp_array );
}