Hello,
But you asked about Server response time issue. We don’t have an issue with the server response time, it takes 511ms https://prnt.sc/13cl43j but your TTFB is 1.9s https://prnt.sc/13cl5yl
Also, enable JS and CSS minification on your site using the cache plugin.
In case you are not satisfied with the theme speed we are ready to give refund.
Regards