Earlier quoted context omitted.
Hmm mine is a Galaxy A21s. /dev/block/dm-4 3.4G 3.4G 22M 100% / /dev/fuse 23G 14G 8.2G 64% /storage/emulated I haven't worked with AOSP in ages, just normal apps. Is root supposed to be 100% full?
Honestly it's been a while for me too and I don't even know how to see the actual device partitions instead of just mounts (e.g. I think in this case your / is just a read-only ramdisk so it doesn't really matter what df says... mine is 100% too.) I don't even know how this works anymore since I think since Android 10 they use some sort of overlay FS for updates? I tried installing parted on Termux but it refuses to…
I will when it starts to annoy me.
Or I may just get a new phone the next time I need to do Android. This one has 12, they're at 15 now. I may need to be on whatever's the latest on a new project, whenever that comes (not soon).