appletreebanana I'm seeking legitimate information and resources that can allow me to properly educate myself on privacy & security, including further info on insecurities of famously overhyped "privacy" material (e.g., Linux, LineageOS, CalyxOS, Firefox and FF Based Browsers, etc). I've found that many of the popular resources currently recommended online are misinformative and bogus (e.g., Privacy Tools, Privacy Guides, EFF, etc).
To most users I work with, "Switch to Linux, get a VPN, get a Proton mail account and set up Element for chats" is an absolutely adequate recommendation to very significantly improving both their security and privacy. Although I haven't read the sources you mention, I hardly believe they are spreading misinformation.
The problem here I think is that what constitutes improved security or privacy is very different for different people.
I person who needs to protect their personal devices and online life from another person they live with needs very different kind of security and privacy features than a person doing activism to fight for improved human rights, which yet again need very different security and privacy features than a company that tries to protect their company secrets.
And different operating systems and software might cater differently much to different user groups and their needs, some may even improve security and privacy a lot for a certain user group while reducing it a lot for another. For example, Windows offers way way better security and privacy for the person who need to protect their devices from someone they live together with than QubesOS does, QubesOS offers close to zero protection for them. Yet, QubesOS is an excellent choice for an activist.
appletreebanana Reading various threads in this forum and relevant tweets from GOS, I've already discovered plenty. So really, how can I learn more, beyond just this forum?
I think what you are already doing is an excellent choice. Read information as you come across it, and be on security and privacy related forums that feel relevant to you. You might also want to think about who you want to protect yourself against, and if the information you read is relevant to your threat model and how.
I think you will find you are learning to improve your security and privacy very rapidly by just continuing to do what you are already doing. Unfortunately I don't know your threat model, so I cannot tell what would be good security and privacy advice for you. And there might not be any blog or website with information that would be reliable for your specific threat model. I could write a blog and a website, but it too might not be relevant to you.