This is like breaking my fingers - I'm so much slower now. It's not just that there's a difference - I can adapt to that. It's that they've re-labeled menu entries with duplicate index keys. You can't do some things quickly now (e.g. optimize column widths with Alt-O-M-O, which worked for years).
There's a reason why MS Excel has keyboard shortcuts that make no sense - they match to menu entries from old versions, and they've kept them in so people who have been using it for decades don't have a reason to switch.
Please, LibreOffice developers, make your menu shortcuts sensible again!