Jitter and Packet Loss

Same old issue impacting many of us, still. 

On PC, connected to Ethernet and ping is generally <50 running an RTX5080. Have tried turning graphics all the way down, rebooting router, confirming UPnP is enabled. Everything. My internet speeds are somewhere around 750/250mbps. Meanwhile, my mate on a 4080 with potato internet is able to play the same game, same servers flawlessly.

Would really love some insight into this.