The HN website shows the host part of the URL right next to the title, so it says "Roam 50GB is now Roam 100GB (starlink.com)", but it looks strange in my RSS reader
Every browser-based bitwarden client I have used have the option to choose the autofill option on single items as well as the global default. Find the login item, click edit, scroll to autofill options, where each URI is listed with a gear icon next to it. Click the gear and select the appropriate match type.
For the absolute majority of use cases, "host" should be the default, but i have found uses for both "base domain" and "regular expression" in some special cases.
Normal browser extension Bitwarden Ctrl-Shift-L autofill defaults to the most recently used entry when there are multiple matches, afaik.