Multi-lingual SEO: how to treat index.html for best SEO

I run a multi-lingual website in which the index.html is a piece of js code redirecting to the respective homepage based on browser language setting, e.g., /en/home.html or /de/home.html.

Now, if I just leave it as it is SEO tools grumble about missing title and meta tag. Also, I actually don’t want it listed by search engines but the respective country home.html. Therefore, I put the index.html on noindex.

My question: will backlinks to index.html still help my website SEO? Or else, is there a better way to do it?

Thanks in advance!