@IDwastakenbefore
The lag does not appear to be connection related
Initially I would be looking at the antivirus and firewall exceptions for both launcher.exe and swtor.exe , try removing and re-adding
have you tried playing on a different PC at all on that connection ? just want to try and see if it is system specific or possibly related to a firewall or flood control enabled on the router/modem
The only other possibility is the routing to the exact IP range is funky but this will involve further testing as will need to establish the exact server IP address which can be done through netstat command.
When the game is running , open a command prompt as administrator and run the following command
Netstat -n -p tcp -b | more
(can copy and paste this command) look for swtor.exe and a port range of around 20000 this should be the exact server IP address and look close to the original IP used
once you have that exact IP address the tracert and pathping tests can be re-run again