Put it like this, any launcher that uses a debuggable "companion' add on has to be "tricked" into believing the device is in the US, Latin America and Canada. According to some people I've spoken too, these users were the first nova users to get a day feed - because it quickly became apparent that Google were involved in so called server side testing or A/B testing. One group of users get the dark option whilst another doesn't. Nova have admitted that their own settings do not have any impact on the Google feed, which would indicate nova behaves and interacts with the Google feed in a different way to other launchers and this will also explain why nova themselves suggested "tricking" Google by changing Google app and default language.

I'm not even convinced how this actually works because even though I have a dark feed and the new discover style, it's not dark every time and can quickly go back light as quick as it went dark, and the style will constantly change from discover without the search bar back to the older feed with a search bar.

Until Google themselves and Nova actually fully explain how this works in a way we can all understand there's going to be this consultant posting and reposting asking how one person has it while another doesn't.

Simple answer is I cannot answer that, I just followed Nova's own instructions and it worked for me.