It definitely is not normal, normal ping for SEA is 200-300 on days when the connection was good, now it is very rare. It is most likely due to the faulty undersea cables again, or at least the route to Anet servers. Also during the early AM hours it can suddenly be perfect ping 200-300 (at least for SEA), but after that it is 1k-4k ping.
There isn't much you can do if using VPN gets you a ban, except wait for the cable to be fixed. Anet will always ask you to fix your side of the connection first, or change ISP etc, because the servers are mostly fine for NA/EU connections, it is only some areas that are affected for few months, that is the time when I quit GW2 and come back later.. even years later haha.