'No such file' when running rm AppleSetupDone from single-user mode

I'm in High Sierra (10.13.6) and recently I renamed my account in Users & Group. Now I lost access to my administrator (so I can't install apps or change settings in System Preferences).

I already tried to solve my problem by following I don't have administrator account on my mac but I can't make it past the

rm /var/db/.AppleSetupDone

command, or maybe I'm doing something wrong there?

However, here's the single-user mode screenshot:

Solution 1:

You need to enter the commands precisely, noting all spaces. If no message is shown, the command was successful, much like /sbin/mount -uw /. Enter precisely the following, followed by ⏎ Enter/Return:

/sbin/mount -uw /

rm /var/db/.AppleSetupDone

• With the first command, there's no need to keep re-running it, and no need to run it differently, it worked first try when you didn't receive an error.
• With the second command, all three tries missed the space between rm and /var. Make sure the space is typed.

You should not receive a message for either command and will be returned to the prompt (#) after each is executed. Finally, run reboot.

Solution 2:

For some reason I could just not find the .AppleSetupDone file anywhere it was supposed to be, and I was also a little confused about whether it would be on the Macintosh HD - Data volume or the Macintosh HD volume, so I eventually just decided to do a find command on all of the mounted volumes which worked great because it turned up under Macintosh HD - Data/private/var/db/.AppleSetupDone for some reason, not really sure why.

Anyway after I found it there the rm command worked fine.

So I guess if you've tried everything and you're still really not finding the .AppleSetupDone file you can check in the directory I mentioned or just run the find command from the root folder /

I did find . -iname "*setupdone*"