I am also having the same issue. Primary language English, secondary is french. The posts are there and the posts are all visible but when you click on the category link from anywhere it just comes up with a 404 error.
Please look into this, I also have rankmath but I cant see how that would cause an issue like that.
Here is the site: hittheroadbill.com
Here is the FR version with broken links: hittheroadbill.com/fr
