Thank you! @vongillus had mentioned that command above and it did work wonders indeed. Is there any way to completely remove flatpak? What does one have to do?
Additionally I had tried to follow @dukla2000's suggestion to supplement the storage with an SD card but whenever I put one (an older and a very new & fast model, both 64 GB, both Samsung) the phone does not boot (green LED, black screen & nothing else), no matter whether I format them as ext4, fat or exfat. (I had used both of them for Megi's multi distro image before reformatting them.) What could be the problem?
Additionally I had tried to follow @dukla2000's suggestion to supplement the storage with an SD card but whenever I put one (an older and a very new & fast model, both 64 GB, both Samsung) the phone does not boot (green LED, black screen & nothing else), no matter whether I format them as ext4, fat or exfat. (I had used both of them for Megi's multi distro image before reformatting them.) What could be the problem?

"Low Disk Space on Filesystem root" after installing Axolotl and Podcasts
