Does the mod support localization? I added the file with the translation to assets (ru_ru.json), but the values from en_us.json are still loaded

I'm assuming you are talking about the advancements right? Like I mention at the bottom of my curseforge page, you need the Translation Advancement pack. Right now, the advancements do not use translations by default and has the text built into them so that server owners do not need vanilla clients to download a translation resourcepack. To change this, download this datapack and put it into your world so that advancements now do use translations and will use your language file.
https://github.com/TelepathicGrunt/RepurposedStructures-Fabric/releases/download/0.0.8/Repurposed_Structures-Translation_Advancements.zip

Lmk if this doesn't work!