A weakness of zombies could be water and I think they should react just like how cats do to water, so they don’t really mind rain but they don’t like rivers and pools etc.
What would fit with that would be water guns:
you can find water guns at swimming pools and beaches.
you also need to pump them up so their range is further.
and I think every zombie should have a different level of how much they don’t like water.
and if you become a zombie the only thing that you have is that you can’t swim.
do you have more ideas?