Help me improve this!

Feels like you wasted a lot of passive points taking all the small passives in a cluster.

Do you use the banner a lot? Seems like you're missing out on a lot of damage with all these persistent skills that I feel like aren't doing a ton for you too when you could take something like Coc or Trinity with the spirit. You have something like efficiency on your lightning spear when you could reinvest some skill points being used on small passives on some mana efficiency or mana recoup effects in the tree and instead use that slot for more damage. Or convert mana costs into life costs and take mystic harvest and invest in some life leech.

Your defenses are weird to me. You have Stalking panther but don't have full evasion pieces on your gloves, helmet and boots so you're missing out on a ton of free evasion. The amount of armour you have isn't really doing much for you imo. I would also path out of the start of the tree into the evasion and reduced movement penalty nodes instead of the attack nodes and path into more damage elsewhere.

I'm pretty sure since you can't penetrate below 0% elemental resistances by default and your sceptre causes enemies to resist you based on their lowest resistance, straight lightning penetration is more often than not, not going to be very beneficial. The 15% elemental penetration is probably the only penetration you need since it's actually going to combo well with your sceptre.

You can get a heart of the well diamond that gives you a lot of evasion, or more gain as extra, chance to be lucky with lightning damage and %mana on kill. And or potentially get a From nothing diamond that allows you to get some critical notables somewhere that could really boost your build.

Skill damage conversion happens first, then gain as extra and other conversion happens at the same time. So, fire damage on your weapon and rings are converted to lightning damage but gain extra fire damage still provides fire damage.

My recommendation is to replace the gloves with something more useful.

Your charge generation is a big problem I'm guessing since I don't see meaningful way to generate freezy charges. It's usually done by taking Resonance and use armour break (armour break III gives endurance charges and Resonance convert them to freezy charges).

For low budget improvement I'll recommend constricting command and headhunter. Those two are really good for both offense and defense. You'll have to choose to go either evasion or armour for your defensive layers, since you'll need a good amount of armour/evasion for them to be effective. Take Iron Reflex if you are going armour and wear Hyrri's Ire if you are going evasion (and wear pure evasion gloves and boots).

Here is my character for reference (I play melee spear build but you'll get the idea) https://poe.ninja/poe2/profile/beleafs-6120/character/DivDepartures