Hugo multilingual aliases

Referring to my last issue, I have implemented this function, but I found that there will be some problems with aliases. For example, my /foo address needs to be redirected to the /boo address, but if I do not set the corresponding ca language file, the /foo address will be redirected to the /ca/boo address. I can create a ca file to set the aliases corresponding to ca, but that will be a huge project. I would like to know if there is any other better way to achieve it.

Handle redirects by configuring your production server.

I think this is still a huge project, and I may still implement it according to the existing logic, but I am more confused about why the /foo address is always redirected to /ca/boo instead of being redirected to /boo. This is Controlled by what?