Big loading time on first segment (seg_1.ts) after loading the manifest

Hi!
I’m new with dealing with streaming, so this is my first implementation of this feature.
I’m experiencing an 10 seconds-ish loading time on the 1st segment on all my videos, tested with both HLS.js and Cloudflare Iframe Player.
I’m also recognizing that this segment is 1.8~2mb, way bigger than the other segments.

Is there a way to tune the first segment loading time and size on cloudflare side? I tried tunning on the application side the maximum buffer size and length, but to no avail.