Hi,
Not sure if it's SEO wise a good plan to list your complete parent tree items in the title! As it's also used in for instance Google. Also you might hit a browser limit at some point.
The Page title is configured in the Settings module. Under Settings -> Content.
You probably have something like {%pagetitle_orelse_name%} - {%prefix%}
Although you could possibly create a macro loop in there, if you really want to get all levels I'd say create a custom macro method that would move all logic to code. Also you could make sure to add caching and perhaps add other requirements like not listing certain page types, skipping 'folders', apply a max length, etc.
https://docs.xperience.io/.../registering-custom-macro-methods