You are talking about two different things.
1) to extract any non-English text from a website, you will have to view the website in a foreign language, usually web site will let you choose your language. If they don’t, you may be able to hack the URL in the address bar and change the locale from something like “en-us” to “fr-ca” - for French Canadian, for example. I have to do this on Apple Support documents all the time.
In extreme cases, you may need to run your browser in a foreign language. Well-designed web sites will automatically detect your language and show you content in your preferred language, if they can. The easiest way to do this is with a secondary web browser like Safari Technology Preview. It’s just like Safari, but different. You can specify what language it runs in via System Settings > Language and Region. (At least, you could do this in Monterey. Apple may have moved it in Ventura.) You can change your entire user interface or change just a single app. Note that this will change the entire user interface of that app to run in the given language. Only well-designed apps will detect this language and only if those web sites have content in that language. Another option is Google Chrome. You can configure Chrome to manually specify your accepted language HTTP header. Then Chrome will run in English, but display web sites (hopefully) in your specified language.
2) The best way to extract content is by using the “Export to PDF” feature. This should work fine for most web sites. If you have to take a screenshot, you can extract the text by opening your screenshot in Apple Preview. Since macOS Monterey, Apple Preview has built-in OCR that will allow you to select and copy any text in an image. It works very well.