I thought the whole issue with manifest v3 is that prevented extensions from being able to block connections? That DNS blocking is actual blocking, while the extension can only do filtering after the connections are made.
No. See:
https://developer.chrome.com/docs/extensions/reference/api/d...
>The chrome.declarativeNetRequest API is used to block or modify network requests by specifying declarative rules. This lets extensions modify network requests without intercepting them and viewing their content, thus providing more privacy.