Translated pages are not duplicates: localized pages "are only considered duplicates if the main content of the page remains untranslated." Declare versions with hreflang in the HTML head, an HTTP Link header or the sitemap (all equivalent). Each version lists itself and all others with absolute URLs, or unreciprocated links are ignored. Codes are an ISO 639-1 language plus an optional ISO 3166-1 region (de-CH); a region alone is invalid, and en-UK does nothing (the code is GB). Google detects language itself and does not use hreflang or lang for that.
<link rel="canonical" href="https://example.com/de/preise">
<link rel="alternate" hreflang="en" href="https://example.com/en/pricing">
<link rel="alternate" hreflang="de" href="https://example.com/de/preise">
<link rel="alternate" hreflang="de-CH" href="https://example.com/ch/preise">
<link rel="alternate" hreflang="x-default" href="https://example.com/">Each version canonicalizes to itself, and x-default names the fallback, such as a language picker. Auto-translating scraped content into many pages is scaled content abuse. International Sites covers multi-country structures.