I have a custom sign up form for people to sign up to our newsletter. this form is connected to Campaigns API backend, i. e. our backend subscribes them programatically. 

there is a second entry point through which email addresses end up in Campaigns contacts: through official CRM integration (CRM -> Campaigns sync).

when these contacts unsubscribe via links in email footer, they end up in "unsubscribed" category in the list which means there are completely opted out.

to resubscribe the only way for them is to visit this link again or a similar one (sent in unsubscribe confirmation). this is not good enough: I want them to be able to resubscribe if they sign up via our custom form again.

this is a completely legal use case: some people come back, fill in the same subscription form including consents and they expected to be subscribed again. I understand from previous topic and my production level experience there is currently no way for this. is this a correct assumption? can someone confirm users cannot directly resubscribe through my 2 integrations (API and CRM sync)?

we do not not want to use Zoho forms for subscription. there is no multi-language for example and generally these Zoho no code widgets are technically not a good solution for our web application, I need my own markup. hence the API integration.