Wiz -> Pyro c2 -> Thauma C3 is THE job for World Bosses. Go full INT or 1:5 or 1:4 con:int and be happy.
Huge DPS with pyro multihits skills alone thanks to the thaumaturge buffs, also VERY strong autoattacks with the Lethargy attribute and enchant fire second damage line. Oh in case you join a party any party member will benefits from your damage buffs, even the weakest ones will do significant damage.
I did pretty well myself with Cryomancer. The famous icewall + psychic pressure combo is very strong even with the very long cooldown and SP consumption, as long as i managed to join the fight early and land at least three Lv 11 walls + joint penalty + psychic pressure combos, the cube was certainly in the bag, even alone vs party.
Bonus video: when you put these two together things get very interesting. This boss here has 5,744,400 HP, see how his HP drops, lol.