Your search is not working because you turn on the “Use Relevanssi for AJAX search” which required the “Relevanssi” plugin. And you contains an older version of that plugin that’s why your search not working.
Screenshot: https://jmp.sh/5YiRi8L
To fix this issue you have to just switch the button from “ON” to “OFF” from the Theme Settings >> Shop >> Use Relevanssi for AJAX search.