How to fix "mount: 'remount'->'/system': No such file or directory"? angler:/ # mount -o rw, remount /system
mount: 'remount'-&gt;'/system': No such file or directory
1|angler:/ #


When I try in Kali Linux in my phone:

root@kali:~# mount -o rw, remount /system
mount: /system: special device remount does not exist.
root@kali:~#


Am I missing something?
You  have added a space between the two options you passed: rw and remount. You need to remove space after the comma , and then repeat the command like this:

mount -o rw,remount /system


This should work. Tested on OnePlus 6.