Press and hold keystroke remap fails (e.g., Ctrl+Left/Right arrow remap to Opt+Left/Right)

Do I understand what you're going for correctly?

You want to hold ⌃L and have the text cursor repeatedly jump back a word at a time, as though you were pressing ⌥←?

If so, this does that:

Jump Back a Word (Repeat).kmmacros (26 KB)

Macro screenshot

(Using the Repeat template, found here.)