As Philip Jaske mentioned in his interview with Becky Nagel, one of the cool things in ASP.NET Core is the ability to rewrite incoming URLs to "fix up" a request. There are lots of reasons to do this, ...

A website can lose not only visitors but search engine rankings as well if the search engine is not able to follow URLs to that site. It is therefore essential to get the redirects correctly in place.

Then you can add a redirect for the old URL with the full path so that it redirects back to the main hostname. As for specifically how to do that in whatever server software you are using, that is ...