Hi there! I checked the site and indeed Surge does not seem to be working. You’ll need to turn off WP-Rocket’s page caching features, and then turn off and on Surge to attempt to set it up again.
Having said that, I also noticed that your site issues a Session cookie on every request:
> set-cookie: PHPSESSID=f7qq83nuauupjbfi68usqmorad; path=/
This is likely caused by a session_start() in one of your plugins or themes. This is a blocker for page caching in general, because a session basically says “treat this user as a unique user”. Sessions should only be initiated when the user takes a certain action on the site, that makes them unique, like add a product to their cart for example. WooCommerce does this correctly.
Try and toggle your plugins to find the offender and note that it could be your theme as well.
Hope that helps!
~ Konstantin