The default behavour should be to redirect to the same page in the default/configured language

I don't understand why the out of the box behaviour is to redirect to the homepage. Any page that's visited should have a page in the default language, it makes sense to redirect to that page.

It's currently possible to partially achieve this behaviour by adding entity.node.canonical and entity.taxonomy_term.canonical to the list in the module config, but it's prohibitive to add every route from Drupal and all contrib and custom modules to this.

I think redirecting to the same page in English should be the default behaviour. The list of routes could be used for pages that people want to redirect to the homepage instead, if there is some reason for that. In almost every case I think people would want it to redirect to the same page in the default language.