How to cancel a PayPal subscription not immediately but at the end of billing cycle?
In the PayPal Docs I only found the way of immediate cancellation.
You want to cancel it before it bills again? There's not much practical difference between cancelling it now or cancelling it a bit before the next billing, then.
There's no way to do the latter, other than scheduling your own API call for the day before.
You're expected to keep your own records of how long users' profiles are active for, so if for example you have a subscription that bills every month, it should be active for a month after the last payment you received. It should not matter when within that month a subscription is cancelled on the PayPal side.