Both initial and repeated installments

For initial, createPayment should just add "save": true parameter in the card object of the request when recurring is true, and save the resulting card_id to the recurringPaymentToken on the response
https://docs.dlocal.com/docs/saving-cards#save-a-card-on-a-payment

Note that card_id will only appear for successful payments.

https://docs.dlocal.com/reference/create-payment
For repeated installments, make createPayment accept recurring_payment_token in params and map it to the card_id parameter under the card object