I had a dumb phone once that got it right.

It had one fixed menu entry called "advanced menu" this replaces the menu with one that has everything (except from "advanced menu" which is replaced with "simple menu").

One of the menu entries is "configure simple menu". This opens the same looking menu as "advanced menu" only clicking any functionality toggles a check mark in front of it.

If a sub menu had less than 3 options it is merged into the parent menu.

One plays with it for a bit and before long it becomes a Japanese celebration of emptiness.

It even had a bunch of sort of redundant options. The sms submenu had something like 8 options of which I only really used "new message" and "all messages" but you could go for "unread messages". It's not like the rest of the menu is gone, its all under "advanced menu".

If the right click menu worked like that some would bother to further configure the simple menu and one could share their config.

To make it clear it is not a "more" button "advanced" could fold out the hidden entries like a harmonica.