If properly configured, a multilingual website will not harm SEO and can even boost traffic in multiple regions through targeted optimization.
You can manage multilingual content using plugins (such as WPML) or a subdirectory structure, and use hreflang tags to indicate the relationship between each language version and its target region, avoiding duplicate content issues with search engines.
Note: Maintain a unified URL structure, prioritize manual translation for key content, and submit separate sitemaps for each language to ensure efficient crawling and consolidated ranking authority.