Automatic message delay - 60, 90 or 120 days from creation date

Hi everyone,

We're attempting to schedule a message from 90 days from the contact creation date. The current message delay only allows up to 28 days or 'custom'.
I'm unable to use custom, as the custom requires a date rather than a set amount of time from creation/transaction.
Is there any solution to automatically schedule a message 90 days after the event without the creation of a new event or list?

For context, we're running API's to a list as a result of a transaction. From here we're using triggers to distribute survey invitations.
We're aiming to test a post service service survey for either 90 or 120 days post service delivery to ensure our customers are 'back on track'.

Any suggestions will be greatly appreciated.

Thank you