RESOLVED! However, read it anyway if you are interested in how to add multiple languages to your mod.

I realized that to create a mod with several languages, you need to create a langs.yaml file, where you need to register languages ​​and ini files. But the problem is that when you try to publish a mod, where the modinilanguages argument is specified, nothing happens. I open the bat file, the console opens for a second, and that's it. Nothing. If modinilanguages is not specified, then the list of languages simply does not appear in the launcher. Perhaps a syntax error?

--modinilanguages="%cd%\\Content"

upd: in general, I found out this:
If you remove --modini in the bat file and at the same time there will be --modinilanguages, then the mod can be published (publish, but not update the existing one through the "update" argument). However, there are no languages ​​in the list either. Moreover, the mod after that cannot be launched through the launcher. Also in the terminal during the download, information appeared that the language mapping file was successfully loaded. Here is the content of my langs.yaml:

german: Mot.ini
russian: MotRu.ini

The ini file Mot.ini says: "vdf=GothMoth.mod"
The ini file MotRu.ini says: "vdf=GothMoth_RU.mod"
(i.e. 2 separate .mod files for each language. I'm not sure if this is correct, but at least it makes sense)

upd2: Problem solved. For those who are interested, the problem was in the syntax. And now I will write HOW to make in your mod, 2 languages.
1. In your mod directory (...Data/ModVdf) you need some .mod files. Each .mod file will be overridden for the language you need (scripts, sounds, biks, etc.).
2. You must create as many ini files in the System folder as you have languages. Each ini file must contain the path to the VDF file of the corresponding language.
3. In the main directory of Gothic (your mod), you create a text document called langs.yaml (be sure to specify the file extension), open this file in notepad, and add the following:
german: [ini filename].ini
Polish: [ini filename].ini
English: [ini file name].ini
Russian: [ini file name].ini
[And then you can add any languages ​​in the same way]
4. In the .bat file (or terminal) instead of --modini=(...) you should add --modinilanguages="%cd%\Content\langs.yaml" (if you have a special mod directory, then the path to quotes need to be changed).

It's all. I tried to explain as simply as possible, but maybe I will make a video on the topic of publishing mods to steam, and in particular I will talk about adding languages.