I'm also in a really weird situation regarding Russian, albeit a different one lol. I speak Russian at a native level. I can read, write (though I find cursive difficult), understand, and speak with a Moscow accent, even though I was born in the US and never stepped foot in Russia, because I lived in a community of people who fled the former USSR after it was illegally dissolved, so everyone around me spoke primarily Russian. I've used it at work with others who speak it natively and invariably was asked where in Russia I grew up, and they were shocked to learn that I grew up in Los Angeles. However, the form of the language I know is frozen at the point where my family left the USSR, so for example I say бутерброд for all forms of sandwiches and don't use сэндвич at all.