Stripe Checkout from Legacy to new migration not working

I have migrated my Stripe checkout from legacy version to the new one. The payment does work, but the success redirect URL as well as the DB update does not work. When I send the request I get redirected to my main page instead of the user subscription page. Also I do get the error:

Could not determine the URL to request: StripeCustomer instance has invalid ID: (no ID)

I already did some research and also visited the migration documentation from Stripe: https://stripe.com/docs/payments/checkout/migration

But I do not get the error. My guess is it is between the lines:

//$payer_id = $customer->id;
                $payer_email = $customer->email;
                $updateTrx = $trx->update([
                    'total_price' => $total,
                    'payment_gateway_id' => $payment_gateway_id,
                    'payment_id' => $payment_id,
                    //'payer_id' => $payer_id,
                    'payer_email' => $payer_email,
                    'status' => 2,
                ]);
                if ($updateTrx) {
                    CheckoutController::updateSubscription($trx);
                    toastr()->success(lang('Payment made successfully', 'checkout'));
                    return redirect()->route('user.subscription');
                }

from:

    <?php

namespace App\Http\Controllers\Frontend\Gateways;

use App\Http\Controllers\Controller;
use App\Http\Controllers\Frontend\User\CheckoutController;
use Exception;
use Illuminate\Http\Request;
use Stripe\Checkout\Session;
use Stripe\Customer;
use Stripe\Stripe;

class StripeCheckoutController extends Controller
{
    public static function process($trx)
    {
        if ($trx->status != 0) {
            $data['error'] = true;
            $data['msg'] = lang('Invalid or expired transaction', 'checkout');
            return json_encode($data);
        }
        if ($trx->plan->interval == 0) {
            $planInterval = '(Monthly)';
        } elseif ($trx->plan->interval == 1) {
            $planInterval = '(Yearly)';
        } elseif ($trx->plan->interval == 2) {
            $planInterval = '(Lifetime)';
        }
        $paymentName = "Payment for subscription " . $trx->plan->name . " Plan " . $planInterval;
        $gatewayFees = ($trx->total_price * paymentGateway('stripe_checkout')->fees) / 100;
        $totalPrice = round(($trx->total_price + $gatewayFees), 2);
        $priceIncludeFees = str_replace('.', '', ($totalPrice * 100));
        $paymentDeatails = [
            'customer_email' => $trx->user->email,
            'payment_method_types' => [
                'card',
            ],
            'line_items' => [[
                'price_data' => [
                  'currency' => currencyCode(),
                  'unit_amount' => $priceIncludeFees,
                  'product_data' => [
                    'name' => settings('website_name'),
                    'description' => $paymentName,
                    ],
                ],
                'quantity' => 1,
            ]],
            'mode' => 'payment',
            'cancel_url' => route('user.subscription'),
            'success_url' => route('ipn.stripe_checkout') . '?session_id={CHECKOUT_SESSION_ID}',
        ];
        try {
            Stripe::setApiKey(paymentGateway('stripe_checkout')->credentials->secret_key);
            $session = Session::create($paymentDeatails);
            if ($session) {
                $trx->update(['fees_price' => $gatewayFees, 'payment_id' => $session->id]);
                $data['error'] = false;
                $data['redirectUrl'] = $session->url;
                return json_encode($data);
            }
        } catch (\Exception $e) {
            $data['error'] = true;
            $data['msg'] = $e->getMessage();
            return json_encode($data);
        }
    }

    public function ipn(Request $request)
    {
        $session_id = $request->session_id;
        try {
            Stripe::setApiKey(paymentGateway('stripe_checkout')->credentials->secret_key);
            $trx = \App\Models\Transaction::where([['user_id', userAuthInfo()->id], ['payment_id', $session_id], ['status', 1]])->first();
            if (is_null($trx)) {
                throw new Exception(lang('Invalid or expired transaction', 'checkout'));
            }
            $session = Session::retrieve($session_id);
            //if ($session->payment_status == "paid") {
            if ($session->payment_status == "paid") {
                $customer = Customer::retrieve($session->customer);
                $total = ($trx->total_price + $trx->fees_price);
                $payment_gateway_id = paymentGateway('stripe_checkout')->id;
                $payment_id = $session->id;
                //$payer_id = $customer->id;
                $payer_email = $customer->email;
                $updateTrx = $trx->update([
                    'total_price' => $total,
                    'payment_gateway_id' => $payment_gateway_id,
                    'payment_id' => $payment_id,
                    //'payer_id' => $payer_id,
                    'payer_email' => $payer_email,
                    'status' => 2,
                ]);
                if ($updateTrx) {
                    CheckoutController::updateSubscription($trx);
                    toastr()->success(lang('Payment made successfully', 'checkout'));
                    return redirect()->route('user.subscription');
                }
            } else {
                throw new Exception(lang('Payment failed', 'checkout'));
            }
        } catch (\Exception $e) {
            toastr()->error($e->getMessage());
            return redirect()->route('home');
        }
    }
}