MacOS applications come in different forms; some are installed as packages, others are completely executed from the menu bar, others as DMG files and others are installed in the System Preferences application.
Depending on how an application is installed, the method to uninstall it will be different. The easiest applications to uninstall are those found in the Applications folders.
The packages are different and if you need to uninstall an application from the System Preferences, the method will be one that you cannot guess. That does not mean it is difficult. This is what you have to do.
Uninstall the System Preferences application in macOS
Open the System Preferences application and press and hold the Control key on your keyboard. Click on the application you wish to uninstall and the option 'Remove the' application name 'from the preferences panel' will appear. Click on it and the application will be uninstalled.
This will remove the application from your Mac. MacOS applications are not installed in parts; If you remove an application from the System Preferences, it will be removed from your system.
Of course, the fact that an application appears in the System Preference does not mean that you have to uninstall it from there. This method is for applications that are installed exclusively in the System Preferences application.
If the application you want to delete appears in the Application folder, you must uninstall it from there. You should also remove it from the System Preferences. If it is still there, try this method to get rid of it, and a system reboot can never be harmful.
In case you have installed an application in the System Preferences and the option to delete does not appear or does not work, it is very likely that the application has been installed as a package. These applications are a bit more complicated to remove, but if that is the situation you are in, you will have to uninstall the package itself.
Uninstalling a package requires the use of the Terminal, or you can find a third-party application that can help you manage packages on your system.
The applications that are installed in the System Preferences are in no way dangerous, bad or poorly developed. It's just that not all applications need to go to the Applications folder, just as not all applications need to run from the Dock or from the menu bar.
The method to uninstall them is not very obvious since the System Preferences do not seem to be editable. Also, clicking and holding them does not make them editable as it does with applications in the Launchpad.