Onlyfun
I seem to have experienced a strange bug with Material Files which made me uninstall it.
What triggers it seems to be scrolling through numerous video files (mp4, webm, gif etc.) , it "feels" like it is not being able to finish the thumbnail preview loading when scrolled too fast (sry I am not a coder). This resulted in the inability to play the mentioned formats in any kind of app. The metadata was loading just not the actual playback in apps like vlc player. Even weirder that this bug manifested on other user profiles too. As well as made the default camera and pixel camera not usable, they would have loaded the interface, while the camera stayed off (also across user profiles, also with force stopping the app and reloading it etc.) I always had to restart the phone in order to take photos again, took me a long time to find out the culprit.
The app has almost 500 issues and now 7 months without an update, I will switch to something else.
And regarding Zarchiver, I used it before, it works great. But it is not FOSS and a Russian dev, if that matters to anyone.
I think I had problems with the default GOS files app initially. When sending multiple files to a USB stick it sometimes got stuck, and the notification frequently showed its still sending 1 file, when it was already finished.
Would prefer something lightweight and FOSS, for now I use default