There are bigger problems to fix in the world than those of trust factors on the internet. This should be easy.

Consider the premise of "How do blind people gain trust and authenticity signals from content they are engaging with online?"

This is an issue that can easily be resolved by enhancing, establishing and enforcing a few simple standards. With the objective that user privacy should be paramount, allowing people to make informed decisions about who operates webhosts and whether they can be trusted when readers are sharing their data.

Most of this should be handled by the web browser, anti-virus programs and accesibility tools. It shouldn't need to be
an overt matter of concern for a user of their device.

Online, and most offline, scams should be treated as a cybersecuity issue, with a rapid cordinated approach. Cybersecurity is principally a SEO issue - improved self identification will improve attribution and ecosystem response time. Amongst many things organisations need to start adopting https://securitytxt.org/.

This is the starting point - What could possibly go wrong?