I wanted to copy an app to the system folder so I tried it using es file explorer but it said read-only so I looked up online and tried mounting it using this command mount -o rw,remount /system
but got this error, what should I do? btw I am using a rooted oneplus 7 with magisk
:/ $ su
:/ # mount -o rw,remount /system
mount: '/system' not in /proc/mounts
1|:/ #