Are there guidelines and/or standards for creating desktop shortcuts during installation?

From here: https://docs.microsoft.com/en-us/windows/win32/uxguide/winenv-desktop

If your users are very likely to use your program frequently, provide an option during setup to put a program shortcut on the desktop. Most programs won't be used frequently enough to warrant offering this option.

Present the option unselected by default. Requiring users to select the option is important because once undesired icons are on the desktop, many users are reluctant to remove them. This can lead to unnecessary desktop clutter.

If users select the option, provide only a single program shortcut. If your product consists of multiple programs, provide a shortcut only to the main program.

Put only program shortcuts on the desktop. Don't put the actual program or other types of files.

My take is this: the installer must ask me if I want a desktop icon - to which I can reply yes or no.

Any app that just blindly and without asking installs its icon on my desktop is a bad installation in my opinion.

Ask for permission - if I deem your app important enough to me personally, I might say yes (but most likely I won't). Give your users a choice - don't just assume since it's your app, it's so darn important to everyone that everyone will want to clutter up their desktop with your program icon.

The same goes for the installation directory - unless you have a very good technical reason why you can't install anywhere, allow me to change the program's installation target directory. Not everyone is a big fan of the "c:\program files" folder hierarchy (I'm not, for one - I like to keep my apps in C:\bin for instance).

So in general: any decent installer should ASK the user installing for these things and present sensible defaults - but always give me the option to change the settings to my liking (to my standards).