Unable to write to /tmp directory in macOS, unable to correct permissions: “Operation not permitted”

1. Reboot your Mac into recovery mode

2. Open Utilities menu in the top bar > open Terminal

   csrutil disable
   

3. Reboot

4. Remove the tmp folder

   sudo rm -i /tmp
   sudo rm -i /private/tmp
   

5. Create tmp folder

   sudo mkdir /private/tmp
   sudo chown root:wheel /private/tmp
   sudo chmod 1777 /private/tmp
   

6. Create the symlink

   sudo ln -s /private/tmp /tmp
   

7. Run repair_packages (you may not need to do this)

   sudo /usr/libexec/repair_packages --repair --standard-pkgs --volume /
   

8. Reboot back to recovery mode and run

   csrutil enable
   

9. Reboot

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Props to Andrew Ferk for figuring out a fix; pulling out your comment as a community wiki answer so it's more readable.

sudo chmod 1777 /private/tmp

Did it for me.