Some backstory:

Been chasing an issue on my Emby media server for a while now (5-6 months to be exact), and have recently fixed it. I don't have many external users, but they always complained about buffering, and i couldn't figure it out.

To cut straight to the point - turns out all traffic going out via port 443 was throttled - see below . The top process is Cloudflare tunnels serving my emby server, the NGINX reverse proxy service what is normally serving Embyvia 443. Look at the difference! 

On the other end i am downloading the same file, one accessing it via emby Cloudflare tunnel, and one via NGINX, on a device outside my home network. look at that utilisation difference on the server! 

Now, i am just a hobbyist, and it took me a while to work it out, so bear with, but to me that looks like throttling occuring? The CF tunnel that uses port 7844 is is nearly maxing out my upload speed (peak times on 900/400) while the on "normal" NGINX way of serving my site via Port 443, it struggles to get past 8 - 15 Mbps, even when it's the only service running.
I also used IIS to serve my media server for a while, but that hit the same speeds, so that leads me to believe its a port issue?

Now to my question - does Quic (or any other isp's in nz) throttle bandwidth on certain ports - just seems strange i can achieve full upload line speed now using a tunnel. Has anyone else had any such oddities?

Bonus photo: Top site via 443, bottom via CF tunnels - what a speed difference!

(And apologies if this is the wrong area - just thought it was relevant to my isp, Quic)

Thanks!

[Mod edit (MF): removed some material)