fees instead of coupons

functions.php

<?php

/* TEMPORARY FEES INSTEAD OF COUPONS CODE */

add_action('woocommerce_cart_calculate_fees', 'apply_10_percent_discount_as_fee');
function apply_10_percent_discount_as_fee($cart) {
    // Avoid applying the fee in the admin or if cart is empty
    if (is_admin() || !WC()->cart->get_cart_contents_count()) {
        return;
    }

    // Calculate 10% discount
    $discount = $cart->get_subtotal() * 0.10;

    // Add negative fee (which acts as a discount)
    $cart->add_fee(__('10% Discount', 'woocommerce'), -$discount);
}

add_filter('woocommerce_coupon_is_valid', 'disable_coupons_when_fee_applied', 10, 2);
function disable_coupons_when_fee_applied($valid, $coupon) {
    return false;
}

add_filter('woocommerce_coupon_error', 'custom_coupon_error_message', 10, 3);
function custom_coupon_error_message($err, $err_code, $coupon) {
    if ($err_code === 100) {
        return __('Coupons are disabled as higher discount is applied.', 'woocommerce');
    }
    return $err;
}