I agree, and the option to change servers is misleading because they all are "seen" by websites as being in eu, or ua with google.
I also get different results with the different browser reflector sites.
These two are good.
It is probably the geoip data base they use, but most web sites will see your location as sweden or central eu.
But not google - even the local city hall site with a google widget on it displays in Ukrainian within the widget. So, you have to change language on most google sites or widgets/signons:
український with an arrow to open drop down list
мова on a menu
That is as good as it gets, unfortunately.
See also https://forums.opera.com/post/157572