Remove WooCommerce checkout add-ons if all products in cart are in a category

remove-wc-coa-all-products-in-cart.php

<?php // only copy if needed

// Remove add-ons if all products in the cart are in the "Gift box" category (and thus gift-wrapped already)
function sv_remove_checkout_add_ons_for_giftboxes() {

	if ( function_exists( 'wc_checkout_add_ons' ) ) {
	
		// holds checks for all products in cart to see if they're in our category
		$category_checks = array();
		
		// check each cart item for our category
		foreach ( WC()->cart->get_cart() as $cart_item_key => $cart_item ) {
        	
			$product = $cart_item['data'];
			
			// replace 'gift_box' with your category's slug
			$product_in_cat = has_term( 'gift_box', 'product_cat', $product->id );
			array_push( $category_checks, $product_in_cat );
		}
    	
		// if all items are in this category, remove the checkout add-ons
		if ( ! in_array( false, $category_checks, true ) ) {
		
			// get the add-ons current position so we know where to remove them from
			$position = apply_filters( 'wc_checkout_add_ons_position', get_option( 'wc_checkout_add_ons_position', 'woocommerce_checkout_after_customer_details' ) );
			remove_action( $position, array( wc_checkout_add_ons()->get_frontend_instance(), 'render_add_ons' ), 20 );
		}
	}
}
add_action( 'woocommerce_before_checkout_form', 'sv_remove_checkout_add_ons_for_giftboxes' );