The caching doesn’t seem to be working

I have enabled a caching plugin on WordPress, and about 64GB of cache files have been generated under wp-content/cache. However, when visiting pages, the HTTP response headers show:

cache-control: max-age=0, no-cache, no-store, must-revalidate
cf-cache-status: DYNAMIC

My domain name is https://circuitcardassembly.com/

This means pages are dynamically generated every time, and Cloudflare is not hitting the cache. My goal is to make the pages generated by the caching plugin actually served from cache.

I have tried:

1. Ensuring proper permissions on the cache folder.
2. Disabling WP-Cron and using system cron to call wp-cron.php regularly.
3. Clearing expired cache and regenerating it.

The question: Why are cache files generated but page requests still bypass the cache? What settings should I adjust to make caching effective?