Enable Classic Widgets
Restores the legacy Widgets screen and Customizer widget panel, disabling the block-based widget editor.
PHPby SnipCraft
php
<?php
// Disable the block-based widget editor introduced in WordPress 5.8.
add_filter( 'gutenberg_use_widgets_block_editor', '__return_false' );
add_filter( 'use_widgets_block_editor', '__return_false' );#admin#classic-editor#gutenberg#widgets