WebAuthn is a W3C standard that can ease the 2-Factor Authentication for phones and computers with a built-in fingerprint sensor. It’s supported by most of the browsers as of 2023.
TTRSS currently uses Time-based authentication code which requires additional software installed on phones. It would be nice to support WebAuthn and use the code as a fallback (like how Github handles this)
you (or someone else) should be able to make an authentication plugin supporting this.
personally though i don’t see the point in dragging this into tt-rss because you can just use OIDC plugin with e.g. authelia which takes ten minutes to setup and has all this stuff out of the box + SSO.
you don’t have to use your phone, bitwarden and keepassx both support TOTP.