One friction point I have out there is that each major OS has differing keyboard shortcuts available, reserved by the OS vendor, reserved by popular global apps registering common keyboard shortcuts, with the net effect being that even for power users, a given app only has 10-20 possible keyboard shortcuts.

I would love to create a collaborative repo that establishes broadly common modern day keyboard shortcut mappings for common actions across OSes (copy is Ctrl+C in Windows, Command+C in MacOS, Ctrl+Insert in Linux), as well as a map of keyboard shortcuts to actions/OSes and if said shortcuts are app specific vs system global.

I'm given to understand historically that Windows intended the Function keys to help with this somewhat, you had F1-F12 (or F24 for IBM Battleship model M keyboard owners), Windows would do Alt+F1, Alt+F2, Alt+F3, Alt+F4 (the latter of which still closes most apps today), and in a magical perfect world where A) every keyboard actually had function key rows and B) there was a conventional place for common actions across apps that could be used, users could learn more than Ctrl+Z, Ctrl+O, Ctrl++ to zoom in (oops, not always), Shift+Insert to paste, Shift+F11 for context menu.