I couldn’t find a suggestion in your videos for my use case and looks like I’m missing something.
Use case:
I create a stripe client and subscribe it to a Plan, with a discount.
The client logs in to the app, and he needs to pay for the Subscription.
In the backend:
Create the Client and Subscribe it, using Stripe.js

Subscribe create,
Payment behavior is Default Incomplete
Coupon, I pass the coupon code

I create the Stripe Checkout Session through API, and save its ID in the DB.
When the user logs in, he is sent to Open External Page , which the Stripe Checkout Session previously created and saved ib the db , URL.
THE ISSUE:
The Checkout page opens, but the amount that is shown to be paid, and what’s paid is the default Price amount, and not the amount_total (that includes the discount).
For example the Price amount is 450$, the discount is 10%, the total amount is 405$.
The invoice created for this subscription is 405$
But on the Checkout page, I see 450$ and I’m charged for 450 instead of 405$.