It's you that's stuck in the past.
Opportunistic pinning from the taskbar itself, and dropping shortcuts into the taskbar shortcuts folder hasn't been necessary for some time, more recently it hasn't been possible.
Firstly you need to pin the portable launcher to the taskbar, not the program it launches. And you do that with File Explorer:
IMO calibre-portable.exe should be shipped with a different icon, e.g put ot in a frame.
BR