Content access in Social 13.x

Problem/Motivation

I am looking for a better understanding of how content is being accessed on social sites now.
@RobertRagas wrote:
As we moved away from node grants so you need to use the SocialNodeQueryAccessAlterInterface

Drupal 10.3 introduced Access Policy API:
https://git.drupalcode.org/project/access_policy/-/blob/1.0.x/access_pol...

There are modules like https://www.drupal.org/project/access_policy →

How do they all work together?

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes