I have noticed apps like custom Menu interferes in the loading of the nextcloud, custom menu is just one example but here we have another app called App Order. So when we are viewing files menu I basically have 3 apps opened at the same time.
The issue might be the apps are not up to date with the version of nextcloud latest update or whatever they use in the background.
I am not php developer, but if with cache you are referring to some php cache !?