I'm playing Witch with Blood Mage ascendancy, please help!

As stated I'm playing bloodmage (lvl78 standard) and I'm finding certain content nigh on impossible to do, I'm trying to play a chaos (Hexblast) build and even though I have really good gear I get stomped by all bosses and my damage compared to other classes/ascendancies is pitiful, it takes me ages sometimes over 5minutes to solo bosses because I do no damage and I get one shot constantly by anything, but when I invite people they'll blow the boss up in 2 seconds. My hexblast is currently doing 16,266 DPS according to the tooltip and all it does it tickle. I've been playing diablo Hardcore for years and I only chose standard because it's a new game to me, I can handle the boss mechanics but I do such little damage it just ends up with me running out of life flasks or getting one-shot even though I currently have 1559 HP and 1797 ES with resistances etc. I've tried to redo my passives trying out loads of different builds but nothing works for me. Trash packs are super easy because of my contagion etc but bosses are a no go which means I'm stuck doing waystones that don't contain bosses and it's almost impossible to run Sekhema to get my 5th and 6th Ascendancy points (even with >70% honor resist and >90% added defences) that I really, really need to start doing decent damage because for some reason they made all chaos spells have a base crit of 7% so even with good gear I can only get Hexblast to 30% crit until I get my other points and I can raise it to 15% base crit. I don't want to use degenerate or exploitative builds like minion death spam I just want to play normally but it just doesn't seem possible? I've sunk soany hours into this that I really don't want to reroll but I've been playing a monk alt and I'm destroying act bosses in seconds with crap gear when I was struggling to solo those bosses as bloodmage. I don't know what I'm doing wrong and I would appreciate some help from anyone experienced with the bloodmage Ascendancy because this situation is making me want to quit PoE.

If you are able to part with hexblast you can check out this build for Witch BM.. looks promising. https://mobalytics.gg/poe-2/builds/lazy-exile-one-shot-bloodmage
updated on Feb 15th.

also other builds for BM listed there.