The option of using Own CDN helps, for example, to server your server GTM within the same IP as your website which prevents the latest WebKit version from decreasing first-party cookie lifetime. 

Below is an example of how to use Cloudflare CDN with stape.

1. Go to your stape container setting and select Own CDN.

2. Go to CloudFlare and configure A record for the tagging server URL. Please make sure that Proxied is enabled. The setting should look like in the screenshot below. 

3. Go to the Rules -> Page Rules (1) inside your CloudFlare account. In the URL setting (2) add your tagging server URL ending with /*. Set SSL to Full (3) and Cache Level to Bypass (4).