luceos ReCache caches pages and requests itself which adds on top of Flarum. The extension I wrote replaces the native file based cache (storage/cache and storage/views for instance) with a redis based one. A redis based driver is also required for the queue functionality in Horizon.
Wouldn't it be a better approach to offload the static assets to a CDN to reduce origin server load ? Pretty much an industry standard these days. I conducted a test by uploading the assets folder into my CDN, then added an NGINX re-write to redirect the connection there. A significant speed improvement, but not dynamic as the assets folder contents would need to be updated on the fly (for example, when a new user registers etc) for it to be usable.