Livewire v4 changed how property hydration/updates work internally, and wire-elements/livewire-strict hasn’t been updated to hook into those changes. In v3 it relied on middleware/hooks that simply don’t fire the same way anymore in v4, so lockProperties() becomes a no-op.
@respect Looking at it's codebase, I think you should be able to create your own component hook which extends Livewire component hook especially update method and simply throw an exception if the property name that being updated was not locked.
Or you could post an issue there to support current Livewire 4