Hi Olly,
I am Maurizio from Pizzeria Carignano, sorry to write here but there is no Rewards Topic in the Extensions section.
By enabling the WPPizza – Rewards plugin I get the error in the WordPress Site Health:
1. Active Session Detected: A PHP session was created by a call to the session_start() function. This interferes with REST API and loopback requests. The session should be closed by session_write_close() before making any HTTP requests.
2. The REST API encountered an error: The REST API is one of the ways in which WordPress and other applications, communicate with the server. An example is the block editor screen, which depends on the REST API to display and save your articles and pages. When testing the REST API, an error was generated:
REST API endpoint: https://staging2.pizzeriacarignano.it/wp-json/wp/v2/types/post?context=edit
REST API response: (http_request_failed) cURL error 28: Operation timed out after 10002 milliseconds with 0 bytes received

I disabled all Plugins and by exclusion found that the error is generated by only this Plugin. I just wanted to report it to you, I have no idea if this may be a relevant error for you.
Thank you.