Doing webpagetest.org page speed tests of that URL have 3+ seconds TTFB which is slow and bad and suggests poor origin server performance maybe even database server performance and/or just the origin is not performing well.
To fully optimise a site for performance and speed, you need to optimize 3 segments.
- segment 1 - connection between visitor and CF edge server i.e. CDN cache, WAF, Firewall, Page Rules, Mirage, Polish webP, HTTP/2, HTTP/3, CF Workers (i.e. custom/advanced caching) etc
- segment 2 - connection between CF edge server and your origin i.e. Argo, Railgun & Full SSL/ECDSA SSL certificates
- segment 3 - your origin server’s performance/optimisations i.e. web server, PHP, MySQL server optimisations and server hardware specs.
Cloudflare can only help for segments 1 & 2 for cached guest/non-logged based visitors. Now for Cloudflare CDN cache miss/bypass and logged in user for web apps like forums/wordpress performance or in your case non-cacheable pages due to frequency of updates, is determined by segment 3.
So dynamic pages’ performance could purely be due to segment 3 factors related to your origin server itself i.e. web server, php and/or mysql database performance which need optimizing and/or better hosting.
As @sdayman suggested, setting a lower TTL for Cloudflare CDN edge cache time might help sometimes, but it will still be slow for non-cached hits until you fix the origin server itself.