Hello,
Take our apologies for the delay in answering.
Error that you provided in Private content is related to back-in-stock-notifier-for-woocommerce plugin. So, contact plugin author to fix that.
To improve the page speed enable caching and also enable Lazy loading for the products elements https://prnt.sc/1zy4rcz
And improve the server response time https://prnt.sc/1zy4xy5
Regards