I was super annoyed by the keyboard vibration as well. You can “monkey patch” it out, it’s described here: https://source.puri.sm/Librem5/community-wiki/-/wikis/Squeekboard#vibration
So “full” does vibration on new messages and incomings calls, but not on keyboard pressing. It’s nice and I always find it distracting to enter the LUKS password, because I don’t find a way to disable the keyboard vibration so early at boot.