"And on Android you can always flash a new ROM over the vendor installed one to remove any bloat"
A lot of manufacturers don't provide bloat-free ROMs, and most Android phones will balk on an unisgned ROM, which requires the manufacturer to sign.
It could simply be a matter of a unique version being available exclusively for Russia. Which means its own signature keys and so on, meaning it wouldn't be possible to install anything BUT Russian ROMs (with their concomitant spyware).
