Am I missing something? Mana Stacking Chaos Archmage but my dmg feels very low

I have 5.2k mana (normally overflowed to ~8k)
My gear is good (i think?) but my main skill (fireball) is still only doing around 25k tooltip dps (against bosses id estimate i do around 50-60k with procs and such).

Its a bit of a silly concept - Blackflame covenant CoEA Chayula monk.

https://poe.ninja/poe2/profile/OishiiJade-4287/character/TeiShii


I have wither and shock, sigil of power etc but im still fighting map bosses for 5+ minutes each (i dont want to one-shot, but this is too slow!)

Am I missing something obvious that would help my damage? Please help! Its sorta miserable despite all my efforts to make it work..