The answer by @ROSt53 (and as implied in the question) will generally offer a workaround, but MacOS has long had issues with its treatment of the Alt / Option key and LO has compounded this. First, the symbol used throughout LO to indicate the Alt / Option key is wrong (fdo#39477): ^
is used to indicate Option rather than Control (which is the usual meaning associated with this symbol). This can be confusing for MacOS users and can give the impression that keyboard shortcuts do not work (fdo#43680). Help file information may not be accurate in this respect.
It is also worth noting the CTRL+ALT+click-n-drag action for spreadsheets appears to be broken (fdo#58440). A similar problem may exist for tables in Writer document (although there does not appear to be an open bug report relating to this).