Thanks for your help earlier — that worked perfectly, and the product structure is now updating as it should.
I’ve noticed one issue though: now that my product structure is updated, my products are no longer appearing in the translated subdirectory categories. At the moment, only the English version of the site is showing all products.
How can I make sure that all my products also display correctly in the translated category versions of the site?
Also, if you're wondering why the links in other languages do not work, it's because you set "product categories" as "fallback in the default language", but there are no other products translated.
I would suggest you set "product categories" as "show only if translated" in WPML > Settings > Taxonomy translation.