Welcome to the community @simon.lab!
Honestly do not really understand what you are doing in general or how the Hubspot CRM and Mailchimp are involved and if they have to be. Can you please be a little bit more specific.
It sounds to me in the most simple form like you want to send out a link to a survey (then do no see why Hubspot, Mailchimp and even Typeform have to be involved at all)? Or do you want to auto generate a totally new one? What is happening in Hubspot and also in Mailchimp? Or are you using the later one simply for sending an email?