Problem with replacing a menu in templates

Hi Kyle,
I wanted to replace the three bars above and below the canvas picture in mobile view with a sliding menu that you also see on google search. I have written the code for it and it works but I do not manage to override the current template code. My PHP code does not get expressed.
Any help on what files to override using the template override?

Those are constructed deeper in CB when tab content is being parsed and arranged. You won't be able to change those from CBs template files. You can however just override them using CSS. Note we've replaced the desktop view of the hamburger menu with a ellipsis for more up to date UX. Mobile is still a hamburger menu as it's the appropriate icon for that usage on mobile.

Any idea how to do it? The CSS option does not work. Create a whole new Menu field plugin? Or create a plugin that overrides some stuff from CB?
I do not want to "hack" anything within CB as I am updating it quite often so need it to work as an override.

The below CSS should work fine to replace the hamburger icon with a fontawesome ellipsis icon.

that is not at all what I want to do. I want to replace it with a scrolling menu just like when you search on your phone something in google (you can scroll it vertically). Nobody actually presses on that menu be it a sandwich menu or an ellyptic menu (as it is one more click). I need to somehow include my own PHP code into the it and I was hoping to be able to do it via the template override...

Sorry, I don't understand what you're wanting. Do you've a concept screenshot or something to show what you're wanting it to do or display as? If you need to output custom PHP you could probably use a Code field in a new tab in the same tab position as the Menu tab.