Coming in 2023 2024! A book that goes through Drupal's cacheable metadata and caching systems from render pipeline to reverse proxies. It is in the early stages, with an outline 90% complete and a few chapters written. I will be self-publishing through Leanpub. You can register your interest here: https://leanpub.com/understanding-drupal-complete-guide-caching-layers

Here is a preview at the chapter and a quick summary

1. Cacheable metadata: tags, contexts, and max age explains the building blocks of Drupal's Cache API: cacheable metadata.
2. Cache items, their backends, and stores demonstrate through interaction with cache items and backends.
3. Render (fragment) cache explains Drupal's render pipeline and how Drupal implements fragment caching for parts of its render tree.
4. Caching responses explains how Drupal implements response caching, and the ability to stream partially cached responses.
5. HTTP caching headers explains HTTP caching headers; these are not specific to Drupal but can be affected by cacheable metadata values within Drupal.
6. Reverse proxies and CDNs explains how Drupal's Cache API can influence reverse proxies and CDNs sitting before Drupal.
7. Debugging your cache walks through debugging Drupal's caching layers.
8. Writing code with cacheability in mind provides examples and tips for writing code with cacheability in mind.