where are the lvl 80 karma vendors
https://wiki.guildwars2.com/wiki/Temple_armor
Berserker prefix exotic armor can be obtained at the Temple of Grenth in Cursed Shore when the Pact holds the Temple. they cost 42K Karma per piece, so you don’t have enough for a full set yet. You’ll want to read the wiki page, as these items are soulbound on acquire and one cannot salvage them to recover expensive runes if/when you want to upgrade to Ascended.
I don’t know of any Karma sources for Exotic Berserker weapons. The best sources for those would be specific explorable Dungeons (like Crucible of Eternity or Citadel of Flame), or just buy them for gold on the Trading Post.