Impending Doom/Elemental Invocation Stormweaver help needed

Hi all,

I followed a couple of guides for a bit, and decided to try and make something on my own - with varying success, since I'm currently a bit stuck. As I have very little POE1 experience, I'm mostly wondering is it a build problem, skill setup problem, tree problem or simply gear problem.
I can do most T15s, and even tho I failed on the 1st try, but managed to take down Trialmaster for the 7th/8th ascendancy points. However, it showed me that my build is definitely not up to the task of pushing for any sort of pinnacle content.

I set some limitations for myself due to liking/disliking certain things:

1. I really hate how wands look, so I'm set on using a staff.
2. I really like how the Morior Invictus chest plate looks, so I'm kinda set on using that as well. However, it can be a different variant. I'm aiming for the Max Mana%, Spirit one, but not enough currency to afford it (this would allow me to run CoI to further increase DPS)
3. I'm aware that Archmage fits perfectly with the idea of scaling mana for impending doom, but I'm not a huge fan of it. If its the only way of scaling forwards, then I guess I'll be forced to use it.

I'm not completely set on Stormweaver for ascendancy, originally I chose it to apply all 3 elements, due to the 'Shock can be applied on all hits node' thinking how it will improve my single target DPS with the 'Stormfire' support gem interaction with burning ground, but it proved to be underwhelming.

I do enjoy Impending Doom for clear, so I would like to keep it, maybe even run the Original Sin, as I could potentially be able to afford it soon.
I also quite enjoy Elemental Invocation since its a buttload of Comets on demand, but I'm aware of how much mana I'm losing by pushing my Dex so high.

I also have an lv87 Infernalist, and the health reserve nodes could bring some power with more spirit, mana, energy shield, but I would have to plug the hole of Chaos Res.

Maxroll: https://maxroll.gg/poe2/pob/n0yh0ftq
poe2DB: https://poe2db.tw/pob/Id3lBKcVS1

To anyone who takes a look, thanks in advance, means a lot. :)