This is controlled by a menu option - CorePortal - Employee Appointment Salary - which can be enabled/disabled via Security.
In Security Dashboard, click on Menu Profiles tab.
Enter name of relevant menu profile (e.g. COREPORTAL_EMPLOYEE) and search.
Click the three-dot menu and select Manage Menu Options on this menu profile.
Enter CorePortal - Employee Appointment Salary in search bar.
You should see the following menu item.
Menu Option - CorePortal - Employee Appointment Salary.
Menu ID - MAIN_MENU.Emp_App_Sal.
Ensure this menu item has its Active toggle switched off.
Users with the above menu profile should no longer see their salary under My Profile.