Is there any easy and effective way to permanently disable that? (Without having to be logged in)

I've found it at least 10X more distracting than useful.

EDIT: There are some browser extensions, or simply change your search URL to include udm=14 as a query parameter: https://www.google.com/search?udm=14&q=%s

They train on your data. Even when you use the api. You have to both have a GCP account, be using the right model name and the api. “Preview” no “experimental”. This is so convoluted and hidden that there’s an argument to be made that that’s by design.