There are a few different ways to modify the settings area of Go High Level using The Marketer's Toolkit.
Theme Builder - Rename & Hide Menu Items
Located in the solution, "Rename & Hide Menu Items" area, the Theme Builder allows for the hiding & renaming of various menu items including settings.
If a menu item is missing, it can be added upon request.
You can turn on/off, or hide menu items from everyone or specific types of users (everyone, sub account admins or users).
GHL Customizer - Menu Edits
Another feature available for menu customization is the 'Menu Edits' option.
It allows you to hide menu items, similar to what can be done in the Theme Builder.
If you are an agency admin, you get a hidden menu item under the user menu on the top right that allows you remove these menu edits.
You can use the feature called 'Location Groups' to group locations (subaccounts), offering more control over which locations receive the menu edits (the Theme Builder is currently a global).
GHL Customizer - User Settings Area
This area lets you hide settings only from Sub-Account Users & Admins respectively. Agency users & admins are unaffected.