@Richard No, I'm using only lay theme for this. I'm adding a category (blog/journal) where I'll put the "blog posts" (projects) as image links.
I've added the category (blog/journal) to the menu (but it's also the same with an individual link added to the menu, that happens to be a category). When the category is opened and one wants to change the language via the language switcher, the category page redirects to the front page, not the translated category page.
Since the language switcher option works on everything else with lay theme (pages, projects, menu points that are not categories) it looks to me like there might just be missing some code that connects the category languages?
Since this can't be solved with adding an individual menu link, because the problem seems to be with the "category" type, it seems to me like it would have to be solved with code to lay theme.
The translations of the categories are present in the backend. Just the switching between the languages doesn't work on the live page.
Please help, thank you!