I bought mudfish subscription for the first time. I enabled full VPN mode and selected KR Asia EC2 server. The ping is 500+ms, which is way worse than other VPN providers that I used. Is there something I am missing? I am connecting the game from Bosnia.
Did you try to change a mudfish node based on FAQ - Nodes section?
I think you can start with the basic node mode rather than the advanced / multi-path node mode. If it works fine, you can try to test with Multi Path Mode.