A few words.
Your game description is very short. You can just write both language versions on the same page. Also, this should work on a game page too, should you need to save space. https://itch.io/t/2151831/adding-spoiler-text-to-your-game-description
Tags are not translated. No one uses the tags you use. Only a handful games use https://itch.io/games/tag-novela-visual , but 44000 use https://itch.io/games/genre-visual-novel
Itch is a English site. Spanish speakers that browse here will have ways to deal with that. Either they speak English or they use the translation feature of their browser or whatever. That means they will not use spanish tags. They know that no one uses those. And games can be sorted by having language features. Even if that feature seems kinda hidden.
Compare how the games in this list handle multi language game pages and try not to reinvent the wheel. The reach impact Hechelion describes will be substantial, if you split your visibility.
