You'd usually simply use a Direct Charge — https://stripe.com/docs/connect/direct-charges. That's exactly how you platform A makes an API call on connected account B to facilitate a payment, and the fees are paid by B.
The link you posted is for a more advanced integration where the platform processes the payment(and therefore pays the Stripe processing fees) and then transfers money to a connected account(like a company like Lyft charging a rider, then transferring some of the money to the driver).
The idea is to use account A to send/split a payment between other accounts (1 or more), as in a marketplace
You can't use Direct Charges to split a single payment between multiple connected accounts such that they all pay the fees separately. The most you could do is make multiple separate charges — like take the card from the customer, clone it to each individual account involved, and do N separate charges (https://stripe.com/docs/connect/cloning-customers-across-accounts) on each of them. I wouldn't really recommend that since it likely leads to more declines and disputes(it's weird to have a shopping cart with 5 items from 5 sellers and get charged by the actual 5 sellers, I would expect to be charged once by the company that runs the marketplace).
If you really need to do this type of business model where you take a single payment and then split between multiple sellers then you do need to take the approach you linked to, and have the platform pay the fees, that's the only way, it's specifically discussed at https://stripe.com/docs/connect/charges#types in detail.
