i have ran some tests with Cloudflare and modpagespeed disabled
disabled minify on both Cloudflare and serverside and flushed caches too.
page speed insights and gtmetrix showed those are minified.
if the web page have 10 files img,css,js,html
Cloudflare not caching all missing at least 2 static resources.
google psi makes sometimes irrelevant results.
i haven’t confirmed about Cloudflare processing every request but
i set browser caching for 8 hours. every time that value not changed. also, cf cache status is always hit. But in google PSI it showing reduce server response time. (if it servers from Cloudflare there is no server delay) sometimes mixed results.
i am caching including html.