When i connect to my jellyfin server to stream/download video/audio the speeds are tied to my internet speed. If my internet speed drops so does the transfer rate from my server. However it seems tied to my internet download speed (which varies from 0.5 to 80 mb/s), not the upload speed(which is usually 2 mb/s), and if i disconect my router from the internet I'm able to react the maximum allowed by my hardware. Is this normal? Or maybe something is wrong, or needs special configuration?
If relevant, I connect to a tp link router, which connects to the router from my isp.
How are you accessing Jellyfin? By its internal IP, or your public IP?
That's weird but maybe the way you have set it up (especially if you use your public IP), it may go through the ISP's rate limiter on the router/modem before looping back to you.
You definitely should be getting full local speed if you're using the private IP unless your ISP's router is configured horribly wrong.
My isp gives me something a public ip like 200.191.57.xxx, but that ip changes and I can't open any port. Then my isp's router's local network is 192.168.0.xxx, my TP link router connects there (to 192.168.0.3 i think). Then my TP link manages ips 192.168.1.xxx. My jelly server is at 192.168.1.10, my devices are at 192.168.1.5, 8, etc.