We activated the GP Premium plugin (with a GeneratePress theme and a custom child theme based on GeneratePress child) but in the GP Premium screen we are not able to activate most of the available features.
We also have the Woocommerce plugin installed before installing GP premium (the Woocommerce customizer works fine but the other elements not).
can you first try disabling the Child Theme to make sure that is not causing an issue.
Then check your server settings to ensure your site has enough PHP Memory – a minimum of 256mg is recommended, but as your running woocommerce i would increase that …. by default most of my starts i start with 768mg and reduce it down if necessary.