At first, thank you for your help, now the ping of those 3 servers have dropped back to below 100ms, rest of servers are faster now as well. However, I did notice that now much less servers answer to ping, also, the connection becomes slightly more unstable on my PC, and much more unstable on my Android phone, I frequently experience de facto connection drops(connection didn't really drop, but download speed are 0 or very low) and not very often, real drops. Sometimes I have to manually reconnect multiple times in order to just watch a 5 minutes long YouTube video. This is getting annoying. Please fix this.
Actually, since your VPN service isn't exactly designed for online gaming, I'm OK with 200ms ping, after all I do have other methods to deal with this online gaming thing. To me, a stable connection is much more important than a low ping.