I'm looking for a pro solution to translate 160-page A5 indesign documents.
I saw that there are plug-ins like Translator PRO that uploads my file to an external server and should return it translated.
I don't like this aspect very much (sending the layout to an external server). Do you know of other professional solutions to translate indesign documents?
You're looking for an automated machine translation service that is resident on your desktop?
100% of the "professional" solutions for automation of machine translation of InDesign documents require uploading your IDML to a remote server. I put "professional" in quotes because I'm of the opinion that any professional translation of an InDesign document that involved machine translation would involve post-MT editing by a human being. But either case - a purely machine translated document, or a document that has been worked on by humans as well as software agents - requires your document leaving your computer, I'd think.
Unless you're asking "How do I automate machine translation on my desktop, which is entirely disconnected from the Internet for regulatory reasons?" I think that Azure lets you self-host an instance of Microsoft's translation AI on your own hardware. DeepL's machine translation product is head and shoulders better than anything else I've seen in recent years; it's what powers the ID-Extras tool that Peter suggested, but if there's a way to host it on-site, it's going to be something in their "Enterprise" tier. Systran has a self-hosted server product that I used successfully in a major project a few years back. There are some other products in the seector that don't require access to external servers, and if you're willing to run an internal server to handle your MT needs, I can make some more suggestions.