The PaymentElement allows you to collect card details client-side and confirm the PaymentIntent directly from that UI. This product doesn't let you first collect card details, create a PaymentMethod to then decide how much to charge server-side. The reason is that many transactions will require a customer action from handling 3D Secure for card details to redirecting to a partner such as Klarna or iDEAL payments and those happen at the time you confirm the PaymentIntent as part of the payment method details collection.

Unfortunately, this means that you will not be able to do the flow you're after. If you really need to build this, the best option is to use the "Card Element" integration which they document here. That will let you collect card details, create a PaymentMethod, and then do a roundtrip to your server to check the card's country and confirm for the amount you expect. You'd then handle 3D Secure client-side if needed.