my site's ttfb is very high.
I used to use jch-optimize plugin to enhance the page load. then when i enabled joomla system-cache plugin, ttfb reduced to under 1 second. bun then after a while suddenly it got up to 3 or more seconds.
what ways is there to analyse ttfb in a joomla site? how can i realize what component or what part of the site causes this?