I have good news for you. This series is actually very recent which is great news as a lot has changed rently due to SCA requirements.
The bad news is that is is really messed up process these days.
It looks like you are successfully initialising stripe.js and it works. Now what you have to do is create stripePaymentMethodId and send it to your controller.
The way the flow should work is that the stripe form should return to you stripePaymentMethodId you can access it like this:
$stripePaymentMethodId = $request->input('stripePaymentMethodId');
And then you charge customer like this:
$payment = ($booking)->charge(($course->price * 100), $stripePaymentMethodId, [
'metadata' => $data,
]);
$booking->stripe_payment_intent = $payment->id;
Can you show your code, please? How are your submitting the form?