First of all, I have to say that Google's Assistant (in English) is far superior to any other that I've tried. That's why google home mini is the only non-apple device I own.
And I understand that Croatia is not that big of a market to develop a language for GA, so I speak to my device in English and I'm fine with that.
What I'm not fine with is that device such as Nest Hub is basically useless if you don't speak English.
For example, I've bought one for my non english-speaking family member, hoping she can use it for clock, alarms, weather, home control, etc. When I turn on the device, it is in Croatian. During the setup on my phone, I get the standard error: 'kGSKErrorDomain -83902.'. Then I change my iPhone language to English to resolve that error, Nest changes to English and stays that way, and can't be reverted to Croatian.
So I would deeply appreciate if you could escalate this matter and urge developers to allow users to set their Nest Hub language independently from Google Assistant language. So that people not speaking GA supported languages could still use the device.
Sorry to hear about the frustrations that you're having with the Google Assistant, I'm happy to help.
I would suggest visiting our Google Assistant Forum and writing to them there as this is a question that they would be able to help answer.
Please let me know if you have any further questions.