I was able to run with Russian language enabled. There are two simple steps:

1. Reconfigure your locales:

sudo dpkg-reconfigure locales && sudo update-locale

In locales to be generated choose (using space key) ru_RU.CP1251 CP1251 2. Set following launch options in Steam, Game Properties -> General:

LANG=ru_RU.CP1251 %command%

Next post gave me a hint: https://stackoverflow.com/a/61114933

I didn't need to install additional fonts, but if you still have problems try to install it with protontrics

protontricks 270790 fonts allfonts

Menu and text in game should be represented correctly. Unfortunately you may play only Tutorial and probably PvP, because in duels and campaigns enemies don't fight (they just stay without actions when their turn begins).

English version works without problems out of the box.