Hi,
The reason you are having this problem is because when I am loading your webpage for the first time in an incognito window in the response header I can see a lot of custom cookies are being added: https://i.imgur.com/iJvLXZn.png
First of all you need to make sure you are not using any plugins that are adding custom cookies to your response header. When Cloudflare sees a response has custom cookies in it Cloudflare does not cache that page thinking that page content might be depended on those custom cookie values.
Now when I hard refresh the page again, those cookies does not gets added to the response header again and as a result Cloudflare caches that page on those consequent loads: https://i.imgur.com/ns7DkC2.png
Also as I can see you have multiple cache plugins installed in your system. Please note:
1. You cannot use the official Cloudflare plugin and this plugin at the same time. You need to choose which one you want to use. If you wish to use this plugin, please make sure that you have disabled the APO feature from Cloudflare dashboard and also completely deleted the official cloudlfare plugin from your website.
2. You cannot use more than one page caching system on a website. So, if you already have any other page caching plugins like WP Super Cache or something installed in your site, delete them from your site and also delete this plugin and then install/setup the plugin as fresh.