what antivirus are you using ?
I don't use any antivirus - only windows defender. It's worth mentioning, that in the past I've had dns related problems in other games, that require launchers. In some cases I asked for help technical support of those games, and technicians would spent whole days with me (on discord, skype or whatever) trying to resolve the dns errors, and in every case, they just ended giving up saying that they have no idea what's wrong with my pc and that it's the weirdest case they had ever encountered. So it's not only swtor. What can be wrong? Are there any, idk, connection/dns tests I could run?
try https://www.windowscentral.com/how-change-your-pcs-dns-settings-windows-10
maybe start with google 8.8.8.8 and 8.8.4.4
just to add the only thing that can override a dns server is a localhost entry https://support.microsoft.com/en-us/topic/how-to-reset-the-hosts-file-back-to-the-default-c2a43f9d-e176-c6f3-e4ef-3500277a6dae
also if you havent reset the winsock on that system https://help.iinet.net.au/resetting-network-adapter-winsock-reset
