There are no key combinations that allow selection of multiple messages. None.
I cannot delete 80 messages one at a time. Especially because Apple sucks at having keyboard options to mouse clicks.
[Re-Titled by Moderator]
iMac 27″, macOS 12.7
I can easily select multiple messages by using the <command> key or <Shift> key as always. No change there. Have no idea what your problem is other than lack of knowledge.
Are you, in fact talking about selecting multiple responses within the same message? Well, I can do that too by using <click and drag> to select multiple responses.
iMessage prevents multiple message selection on macOS Monterey
