When editing a post with multiple tags and categories attached to it, it takes lots of time to update. Sometimes it can take more than a minute. When I investigated, I found that most of the time was taken in the purge requests ( anywhere between 500ms to 1.3seconds per request).

My Setup

WordPress 5.7, Nginx (based on WordOps), WPFC cache with PHP 7.4.
Server: AWS t2.xlarge, OS ubuntu 20.04
Neingx helper plugin version 2.2.2

The site is behind Cloudflare