Grub menu still appears on Zorin 17

Grub Customizer saves configuration files outside of the normal paces, and I am not even sure where they all are. It's been years and I have yet to untangle it.
While I can understand that from your point of view, you would not believe that Grub Customizer is involved (and perhaps it isn't. Perhaps...), just having it throws a very large and unpredictable wrench into the works and makes any sort of troubleshooting much harder.

Our hands are tied in checking the normal things, since there can and will be other configurations saved elsewhere.

Any fix for this issue?