Preferences keyboard shortcut should be Cmd,
Please change the keyboard shortcut for Preferences to Cmd,. (Command-comma)
That is likely in the Human Interface Guidelines, although I've never read it. Regardless, every Mac app (within two decimals of every) uses that as the shortcut, including cross-platform apps. (I have 175+ apps, and 175 of them use it.) It's pretty much hardwired muscle memory for a Mac user.
Thanks!