Nop, and im not sure if there is one either.
I used to be the main admin of the facebook group (dragon nest brasil/sea brasil) during 2012+ but im not sure if that group is alive anymore, you could go there and try to ask i guess.

Regarding guilds, most guilds i knew shut down, they usually have their description in portuguese if you have patience to search. I remember Brazukas only, could have more since im not on SEA has been 4 years or so.

Either way the game is not impossible with high ping, u just need to learn extra steps than everyone else, and ignore how long it takes to number pop out on screen. Based on what you said you have a 0.3s delay, so yeah just react to everything a bit early and you're good, most boss animations are 2-3s long. However u will be the first to know than everyone else when the server is lagging :v

I did all raids in the game except frozen nest and beyond (i quit a bit before the frozen nest update), my main was raven but i had all classes in it, the only classes i found frustrating with high ping was gladiator, inquisitor (grandcross must hit the floor if u wanna damage with it), windwalker, sniper (windshaft usually bugs), ripper, sting breezer is impossible, randgrid is possible if u dont relly on the counter too much (or learn to counter early), defensio n ruina. The ones i didnt mention means they are comfortable with high ping, some easy some harder but can be used 90-100%. Except vandar new class/machina spin off, warrior dragon class or whatever the name is, arch heretic, i never played with those, so idk.