Grab relational data in notion and update subscriber in mailerlite

Goal: Assign people to a group in Mailerlite based on their category in Notion.

Problem: I don’t know how to access the categories in Notion via make.com.

The process, I wanna build:

→ watch notion database (people) for changes/data in the relational field “categories”
→ Filter: if (person) is in category A
→ add subscriber to Group A in mailerlite

Somehow I cannot get the filter work.

Can you help?