Ability to change interface language to Russian

It would be great to have an ability to change the language of the interface to Russian and to be able to install the browser with interface language default to Russian

You can, @aayaresko. See https://support.brave.com/hc/en-us/articles/360017901232-How-do-I-change-my-language-

Menu → Settings → Additional Settings → Languages → Language → Add language
P.S. Russian localization isn’t perfect, but you will understand what you do.