SEO issue / hreflang in VM

[VB74]

Hello,

I have a problem with VirtueMart regarding the SEO of my product page:
https://casa-bandera.com/shop-italian-cookbooks/ebook-qs1

The page is highly optimized (and translated into 5 languages), but on Google it ranks very poorly. Strangely, the category page (which is also my shop homepage) ranks much higher:
https://casa-bandera.com/shop-italian-cookbooks

From my research, the issue seems to be that the 5 language versions of my product are not linked together.
When I switch languages on the product page, instead of landing on the translated product, I'm redirected to the category page.

Also, I noticed that my product page is not included in my sitemap, which probably makes things worse for Google indexing.

My question: how can I properly associate the 5 versions of my product so that the language switcher leads to the corresponding product page (and not the category), and so that Google recognizes them as alternate language versions (hreflang)? And how can I make sure that the product page is correctly included in the sitemap?

Thanks a lot in advance!

[ViPeS]

how can I properly associate the 5 versions of my product so that the language switcher leads to the corresponding product page (and not the category)

Use the mod_virtuemart_languages VM module to switch languages