I’ve read that if you’re trying to overturn a habit with a new habit, it’s best to undo whatever it is you did the old way, then redo it the new way.
So if you want to use ctrl-r, but you’re using the up key, use the down key to navigate back to a clear line, then use ctrl-r. Do it enough times and your brain will work overtime to find a shortcut (aka just doing it the new way).
"Use Ctrl-R for fuzzy history, or Ctrl-P/Ctrl-N for history entries"
(I have those bound to bindkey '^P' up-history and bindkey '^N' down-history instead of up and down arrow's "up-line-or-history" which is really annoying with multiline commands)
So if you want to use ctrl-r, but you’re using the up key, use the down key to navigate back to a clear line, then use ctrl-r. Do it enough times and your brain will work overtime to find a shortcut (aka just doing it the new way).