There are some PRs:

• Older attempt to rewrite docs: [Pre-Draft][WIP] Started rewriting Security component docs #5463
• Newer attempt to reorganize all contents: Revamped the main security article #7293

There are some issues with ideas:

• Authentication is not clearly explained (Authentication is not clearly explained #6823)
• Better explain roles, attributes, expressions, ACL permission maps, etc. ([DX] Fix the documentation about the Symfony security #4158)
• Rewrite Firewall introduction (Rewrite firewall introduction #4759)
• Add article showing an overview of the internals ([Security] Add article showing an overview of the internals #5289) (Security documentation: The Big Picture is missing #7532) ("Deep into" articles #7297)
• Explain key concepts (e.g. Token), add flow diagrams, etc. (Symfony security component documentation is bad structured #6861)

Now, let's make some decisions about what to do with this.