Do a search for user in backend workflows

I managed to integrate Stripe and webhook to my app that runs now well.

From the webhook data back from Stripe, I need to control the following workflows based on the success/failure of a Stripe payment. Here, I am facing a problem.

I need to search a couple of data types created by current user, who makes the payment, and continue the consequent workflows. But, I am getting relevant updates on the destination data types’ fields. Creating a new data works fine and making changes to a thing doesn’t, and I am assuming that “Created by = current user” is not the way in the backend workflows, maybe?

Could anyone help me with this setup?