There may be some problems in this area, as suggested by
Issue 92094. I know you're not trying to use Drag and Drop, but at one point in the issue log the problem reporter mentions that determining which modifier keys on the Mac keyboard have been pressed is not working correctly. It looks as if that fix might be scheduled for 3.3 and available soon. I also cannot get Control shortcuts to work reliably when defined via the Tools, Customize dialog. For example I defined ^0 to be Lowercase and pressing ^0 does not set the cell to lowercase, however ^⌥0 did work. I'd like to be able to use the predefined ⇑^2 (Exponential format) and ⇑^6 (Standard format), but nothing happens when I press those key sequences.
However, if the function that you want to perform is on a menu, there's another way. Go to Apple menu, System Preferences, Keyboard, Keyboard shortcuts, Application Shortcuts, "+" box, Application=OpenOffice.org.app, Menu Title={desired menu item}, Keybord shortcut={press desired keys}, Add. If the function you want to perform isn't on a menu, first use Tools, Customize, Menus to put it there somewhere. When you press the defined keyboard shortcut, OS/X finds the menu item in the OOo menus and selects it for you. You can use this function in other applications as well.
Mr. Programmer
AOO 4.1.7 Build 9800 on MacOS 10.14.6. The locale for any menus or Calc formulas in my posts is English (USA).