Can I disable incognito mode in Google Chrome?

No, just don't use it.

 

1. Hold down the Windows Key and press “R” to bring up the Run box.
2. Type “regedit“, then press “Enter“.
3. Navigate to “HKEY_LOCAL_MACHINE” > “SOFTWARE” > “Policies” > “Google” > “Chrome“.
   Note: You may have to create the “Google” and “Chrome” folders.
4. Right-click “Chrome” and select “New” > “DWORD 32-bit value“
5. Give the value a name of “IncognitoModeAvailability“.
6. Double-click on “IncognitoModeAvailability“. A box will appear where you can set the value data to “1“.
7. Restart the computer, and the option to select “Incognito Mode” in Google Chrome will be gone.

Alternatively, you can download this registry import file and run it to set the changes for you.

MacOS

1. 1. From the Finder, select “Go” > “Utilities“.
   2. Open the “Terminal” application.
   3. Type the following, then press “Enter“:
      defaults write com.google.chrome IncognitoModeAvailability -integer 1
   4. Restart your Mac. The Incognito Mode option will no longer be available

 

I found this app that will work on Android, but it's $2. I think it's worth it though.
https://techwiser.com/disable-incognito-mode-in-google-chrome-for-android/