On page load, you have a workflow to create the payment_intent_client_secret and set it in the stripe element. All the actions on this workflow are disabled. Could you try to activate them, republish and see if it’s working?
I had disabled this workflow on the page, to try it directly on the application (settings/general/workflows) (and not on the page), but that didn’t work either.
As you told me, I just reactivated the workflow and all the actions it contains. And republish, but Stripe still doesn’t appear.