@smelchionda 

It is inside AutoCAD 2022 application folder.

The full path is:

/Applications/Autodesk/AutoCAD 2022/AutoCAD 2022.app/Contents/Resources/PopMenuRoot.cui

To get inside AutoCAD application folder - locate AutoCAD 2022.app, right-click on it and select "Show Package Contents"

Use plain text editor to edit it.

Don't forget to backup original CUI file in case something will go wrong.