If I understand it correctly, each sales/marketing mail that get sent out is stored in Swipe One's database and is tied/linked to the CRM entry of the receiver of that mail.

Would it be possible to use the ID of that mail as a dynamic link parameter, so that the ladingpage receives it via GET parameter. With that the landingpage itself could send an API call back to Swipe One with that mail ID to receive the full dataset of the receiver (Name, Company, City.. + all custom fields), so that this data can be used to hyperpersonalize the landingpage tailored to the receiver.

Alternative you could put some of the data into a JSON, base64_encode it and send this as GET parameter directly to the landingpage for hyperpersonalization.

https://demo.com/landing?mailid=m1g23bf45

and/or

https://demo.com/landing?myparam=[BASE64 ENCODED JSON]