Disable Block Editor Site-Wide (Use Classic Editor)
Forces the Classic Editor for all post types by disabling the Block Editor globally.
PHPby SnipCraft
php
<?php
// Disable Gutenberg for all post types; Classic Editor plugin handles the fallback UI.
add_filter( 'use_block_editor_for_post', '__return_false', 10 );
add_filter( 'use_block_editor_for_post_type', '__return_false', 10 );#admin#block-editor#classic-editor#editor#gutenberg