Another possible adaptation might be a return to the concept of third-party introductions and vouchers.
This borrows in part on the PGP Web of Trust notion (which ... has its severe limitations and implications), as well as the "Yale Wall" notion from Lawrence Lessig's Code and Other Laws of Cyberspace", in which anonymous* posts to a physical bulletin board on the Yale campus would be left posted if they had been signed vouched by some third party, essentially indicating that the content was worth viewing.
(HN's own "vouch" feature seems to have echos of this.)
Letters of introduction or credit (a common feature of 19th century novels, see Dumas's The Count of Monte Cristo) would of course require some modern scaffolding and reenforcement, but seem one possible option. It should also be noted that even a vouched or introduced entity or communication need not be a trusted or trustworthy one. Betrayals and turns of allegiance are as old as history (Aleric I, sacking Rome, Enkidu in the Epic of Gilgamesh, ...). But as a probabalistic measure of trust they are useful.
Attestations and elements of personal knowledge offer some assurance, though as Klein and Kelsey Parker note, a well-known columnist and podcaster who's shared many details of their private life might have difficulty in distinguishing a trustworthy vs. malevolent interlocutor.