Unfortunately from all research I've done and direct communication with my ISP and NTT there is very little you can do other than slap the VPN band-aid on it and hope it fixes the issue. NTT basically told me to F*** off because I'm not their customer and unfortunately there is nothing my ISP can do about it since it isn't on their side D: I share all of your pain since this has been an on and off issue for 2-3 years with NTT but I've tested the VPN on all 4 of our computers and it seems to resolve the latency and packet loss issues.