From the HTTP headers it looks like you are using Ezoic and Cloudflare. Is that correct? I’m not sure what it does, but that might be another factor for perceived slowness.
My recommendation: Start with a simple setup without any proxies or putting your Discourse behind Cloudflare. Make sure it’s reasonable fast and only then start optimizing by following Enable a CDN for your Discourse or, if you really want to use Cloudflare, Full site CDN acceleration for Discourse.