Here I have highlighted all of the "Application Data" TLS payloads from the server when I launch the EA app via my phone hotspot and when I am reasonably sure that they are websocket replies. In this case, my friends list shows up (it is not blank and it behaves normally). Therefore, I can infer a correlation between the friends list not loading and the server not replying to me on my home connection. Again, this isn't an ISP issue, as if it was, the connection would be terminated or the ACKs wouldn't get through and the packet captures would be filled with retransmissions (there was just one in the above capture and it was on another port anyway).
If you are unable to interpret this information, please pass it on to someone who is able to interpret it.
EDIT: After extended verification, I have determined that my ISP blocks TCP port 9000, which is the cause of this issue. It turned out that the retransmission was not just because of my trash wifi. This should honestly be documented somewhere, I've pulled my hair out for like two months at this. Packet capture will still be attached for documentation purposes.
TL;DR: If your ISP blocks port 9000 (it was used a long time ago by a virus, but they're stuck in the past i guess), ask them to unblock it or split-tunnel it with a VPN, as that is the cause of the friends list not working.
To check if you have this issue, attempt to open http://portquiz.net:9000 (needs to be HTTP, not HTTPS)
If it loads infinitely and the server doesn't respond, then your ISP blocks port 9000 and you need to VPN it somehow, potentially by using two layers of WireGuard (once into WSL, and another time to a VPN server) and using policy routing if you're going the split tunnelling route, as Windows doesn't have policy routing. In 2026. Otherwise, a VPN will work just fine, although you will experience higher ping.
