Also there’s a keyshortcut for the Sequencer area, “Pattern Sequencer:Edit:Insert Repeated Selection”. This will duplicate your selection in the sequencer.
–EDIT
(This I mentioned, because you noted that it can only duplicate ONE pattern. This will duplicate all selected patterns.)
You do know the Sequencer and the Matrix are different areas, each of which can have Focus and has its own keyboard shortcuts when focused?
Something additional you might find useful: You can make broken (non-continuous) selections within the Matrix by Ctrl+Clicking on blocks. Then you can copy matrix blocks to a new pattern in one go even if they are not next to each other.
Yes Ctrl makes copies, Alt makes ‘aliases’ or just instances of the exact same pattern (like pointers)
so Ctrl is fitting if you still want to make changes like add a master volume’s fade out at the end