While I prefer deeply nested menus (and I acknowledge I'm a weirdo at that) there's plasma-manager if you happen to use Nix and home-manager. I don't know if it will help in that specific case but if you'd rather have the config in a well documented file this could generally help.
Nothing wrong with nested menus. The problem is that plasma has a classic File menu inside of a hamburger menu hidden under a "More" button with a whole set of duplicated options that can be found in other parts of the interface. It's nuts.
I'd rather have all that mess removed and settings 1% of the user base "needs" moved to a config file. I don't want to add an another layer of complexity with external configuration tools.