username is not in the sudoers file. This incident has been reported to the administrator.

Navigate to the /etc folder containing the sudoers in Finder and enter Time Machine and restore your sudoers file from your Time Machine backup. Use Command-Shift-. to toggle viewing of hidden files. This is the quickest approach.

If you’re in the “YOLO club for data preservation”, make a Time Machine backup now, wipe the Mac, use Recovery to install Sonoma, and migrate your login in from your just-created backup.

Since you probably won’t want either of those approaches (“for reasons”), create a sudoers file somewhere else using vim (probably using set paste), pico, or whatever and paste the macOS 13 Monterey sudoers contents below, and then use Finder to copy that file into /etc and authenticate when requested. Restart.

#
# Sample /etc/sudoers file.
#
# This file MUST be edited with the 'visudo' command as root.
#
# See the sudoers man page for the details on how to write a sudoers file.

##
# Override built-in defaults
##
Defaults	env_reset
Defaults	env_keep += "BLOCKSIZE"
Defaults	env_keep += "COLORFGBG COLORTERM"
Defaults	env_keep += "__CF_USER_TEXT_ENCODING"
Defaults	env_keep += "CHARSET LANG LANGUAGE LC_ALL LC_COLLATE LC_CTYPE"
Defaults	env_keep += "LC_MESSAGES LC_MONETARY LC_NUMERIC LC_TIME"
Defaults	env_keep += "LINES COLUMNS"
Defaults	env_keep += "LSCOLORS"
Defaults	env_keep += "SSH_AUTH_SOCK"
Defaults	env_keep += "TZ"
Defaults	env_keep += "DISPLAY XAUTHORIZATION XAUTHORITY"
Defaults	env_keep += "EDITOR VISUAL"
Defaults	env_keep += "HOME MAIL"

Defaults	lecture_file = "/etc/sudo_lecture"

##
# User alias specification
##
# User_Alias	FULLTIMERS = millert, mikef, dowdy

##
# Runas alias specification
##
# Runas_Alias	OP = root, operator

##
# Host alias specification
##
# Host_Alias	CUNETS = 128.138.0.0/255.255.0.0
# Host_Alias	CSNETS = 128.138.243.0, 128.138.204.0/24, 128.138.242.0
# Host_Alias	SERVERS = master, mail, www, ns
# Host_Alias	CDROM = orion, perseus, hercules

##
# Cmnd alias specification
##
# Cmnd_Alias	PAGERS = /usr/bin/more, /usr/bin/pg, /usr/bin/less

##
# User specification
##

# root and users in group wheel can run anything on any machine as any user
root		ALL = (ALL) ALL
%admin		ALL = (ALL) ALL

## Read drop-in files from /private/etc/sudoers.d
## (the '#' here does not indicate a comment)
#includedir /private/etc/sudoers.d

De nada.

I would encourage forfeiting any membership in the YOLO club however, and getting Time Machine or some other backup strategy going. Errant commands involving sudo can do substantial damage to user data stored on a Mac.

FYI, it is never a good idea to edit the actual "sudoers" file. The better way to modify its behavior is taking advantage of the ability to create individual configuration file changes to the "/etc/sudoers.d" folder instead. You utilize the same format and you get to modify "sudoers" behavior without risking the default source file. In fact, this method allows you to have unique changes within individual files making it easier to see & manage the changes (you really shouldn't have very many modifications since those changes may not work exactly like you expect....meaning they could have unintended side effects).

Also, if you are not comfortable with using "vim", then you can instead use the "nano" editor, or any other command line editor you wish. Here is how you can add a custom "sudoers" configuration file called "mychanges" using the "nano" editor:

EDITOR=nano  sudo  visudo  -f  /etc/sudoers.d/mychanges

This will warn you on saving the file whether any syntax errors are detected. If you want to use the default system editor instead of "nano", then just remove the "EDITOR=nano" part.