Need to create an immediate-charge Invoice in Stripe

I need to create an “immediate-automatic-charge” invoice in Stripe using Webhooks by Zapier (there seems to be no built-in invoicing method in the Stripe App on Zapier). I will settle for a “charge later” invoice if that is easier, but ultimately it seems like a daunting task to do anything in Stripe where one-time immediate payments are concerned.

1. In this case the customer will have already existed in Stripe and we have the customer ID
2. The customer will already have a default payment method on file, so the invoice will just charge against that.
3. The item(s) being charged on the invoice is already a configured product in Stripe, so we have the price ID for the item.
4. if the customer has a coupon code, it is a code that already exists in Stripe, so we already have the promo ID for that coupon.
      
5. I want to be able to create a single webhook process to create an invoice with products, coupons, and automatically charge them “today” against their default payment method.

Ironically, I have no problem creating a subscription in a single webhook process that does pretty much all of the above on a monthly or yearly basis; but a one-time charge invoice seems like pulling teeth?!?

Stripe’s support docs seem to be all over the place on this, and guide you to creating an invoice in a minimum of 3 different webhook processes, or promote making an invoice and sending a payment link to the customer.

Surely, someone out there has found a simple way to create a one-time charge “today”, but I’m at a loss so far.  The one thread that was created almost a year ago, on the same subject, was closed for comments and had no solution in it.