Your landing pages should detect the language settings on the end users phone and returns content in that language. If a language is not provided (by you), you should provide a default fallback language (e.g.English)
You can add as many translations as you like for any given POI, but default language must be provided for all your POIs
Make sure all translations of the same POI share the same URL - only one QR code should be needed for each POI
You can add new translations at any time
Automatic translation of content (e.g. with google translate) is not recommended. Build trust through quality.