Garmin devices have historically had two regions for languages: Asia and everywhere else. I suspect this is due to some legacy limitations in their proprietary OS around Unicode support. Years ago, it was very difficult to implement full support for all languages on a single device with very limited hardware and battery power.

Historically, in order to get support for one of the Asian languages, you typically had to buy the watch in the exact right country, not anywhere else.

So how bad is it if you're "just" eastern european? I.e. latin alphabet but extra squigglies and ofc not an en_US locale.