Front page of my site is not being cached

I’ve been working to cleanup and optimize our WordPress site and noticed that after removing WP Rocket from my plugins list (We’re using SG Optimizer for our primary caching plugin now), the homepage load time ballooned out to 10 seconds. After contacting the webhost, they ran an HTTP GET request against the site, which returned the following info:

Antonia-Nikolova:~ antonianikolova$ curl -IX GET https://www.midstory.org
HTTP/2 200
server: nginx
date: Thu, 07 Jul 2022 15:29:23 GMT
content-type: text/html; charset=UTF-8
vary: Accept-Encoding
access-control-allow-origin: https://www.midstory.org
set-cookie: PHPSESSID=5e46dc3d2372c4aa67bf732d8ea1177e; path=/
expires: Thu, 19 Nov 1981 08:52:00 GMT
cache-control: no-store, no-cache, must-revalidate
pragma: no-cache
x-cache-enabled: True
link: <https://www.midstory.org/wp-json/>; rel="https://api.w.org/"
link: <https://www.midstory.org/wp-json/wp/v2/pages/4766>; rel="alternate"; type="application/json"
link: <https://www.midstory.org/>; rel=shortlink
x-httpd-modphp: 1
x-endurance-cache-level: 0
x-nginx-cache: WordPress
host-header: 6b7412fb82ca5edfd0917e3957f05d89
x-proxy-cache: MISS
x-proxy-cache-info: 0 NC:000000 UP:SKIP_CACHE_NO_CACHE

They told me that this indicates that my homepage is not being cached, and later, I checked in the “Test URL Caching Status” section of the SG Optimizer plugin and confirmed that the homepage is not being cached. To troubleshoot this, I confirmed that the SG Optimizer plugin has no exceptions for caching made for the homepage. I also disabled all but the plugins for my theme (Newspaper) and confirmed that none of the other plugins I’m using are responsible. Are there any simple ways to determine what is preventing the front page from being cached? Is there a simple setting somewhere in WordPress that I’m just missing?