on Windows I can press Alt and see a letter underlined in the menu to let me know what keyboard shortcut activates itHave you not noticed that every MacOS menu item that has a keyboard shortcut has the entire shortcut listed on the right side of the menu? This goes back all the way to System 1 in 1984: https://web.archive.org/web/20140512112637/http://www3.nd.ed...
It's somewhat more obvious when you're using a keyboard that actually has all the same symbols on the meta keys; Apple likes to drop those sometimes and it's really not helpful for someone who hasn't learnt the cryptic glyphs. The ancient Magic Keyboard on my desk only sports a ⌘ on the Command key, and lacks ⇧ on the shifts, ^ on control, and ⌥ on the alts.
You can even navigate the menus entirely by keyboard, if you turn on "Full Keyboard Access" in the Accessibility prefs. https://support.apple.com/guide/mac-help/navigate-your-mac-u...
but if I want to "show package contents" of an app in the Applications, I definitely need a mouse!
With Full Keyboard Access on you can hit tab-m to bring up an app's right-click menu and navigate to it. FKA has a lot of tab-something shortcuts.