i have to sites
in one of the, the ajax search work perfect and the ather not find products https://www.sol.seo-stbs.com/ – this is the good one and it fid product in hebrew
Could you please disable all plugins that are not related to our theme and provide us your admin access so we can check it? Also, check your footer widgets and copyrights. There is some unclosed HTML tag there that breaks your website structure.
Could you please check how it works with some default WordPress themes like TwentyTwenty or WooCommerce Storefront to understand is it our theme issue or not?