A Turkish exporter does not appear in German search by translating the whole site. The page that has to be in German is the record a German buyer searches for: the product or service, conformity, the market you can ship, and a contact who answers in German. The Ankara production page does not stand in for that record.
Which page is German
The German URL explains, on its own, the work searched in Germany. Dimension or scope, the standard, the delivery market and who replies sit on the same page. A machine translation of an about page does not carry that question. Without the page there is no twin for hreflang to point at.
Which page stays Turkish
A Turkish tender, the KVKK notice and a local note from the Ankara office are not pages for German search. Forcing them into German fills the crawl queue with copies. Language is proof of a market. A language button on every URL does not open one.
The contact is part of the language
The form on the German page should arrive in German, and someone should be able to answer in German. A desk in Berlin is not required. A false desk is not allowed. If production is in Ankara, the page says so and names the German-speaking contact. An invented Munich address comes back in sales and in any answer engine that quotes you.
Same path, separate intent
TR and DE can share a path. They do not have to share the copy. The German title carries the words a German buyer uses. It does not have to be a literal twin of the Turkish title. EN mirrors the two markets. It does not open a third commercial promise.
Discovery needs the three records a German buyer searches for, the delivery market, and the person who answers in German. An office address is not invented. If production is in Ankara, the page says so.
Which record opens in German is written in the SEO agency brief. If the page does not exist yet, website development is the same scope. The language proof: exporter language proof.