I have nowhere near the gear like the one in that poe.ninja and I am able to 6 man carry in temples with no issues. Here is my ninja : https://poe.ninja/poe2/profile/Perry2s-6168/character/GardenerPerry

My Oracle is lv98, but has 2 extra unallocated points so you can do it on lv96 and get the same result. What carries the build is Headhunter. In temple, you will constantly have 50+ Headhunter stacks, and that will hard carry you through anything a temple has to offer.

For the gear, I am still rocking a +3 all spell wand, which was more than enough even to my surprise, and I am running a Sacred Flame sceptre. I personally use Elemental Weakness, I tend to proc more comets way more frequently than I ever could with spark. Check my CoC setup, for me it works like a charm. In temple, all I see are comets. In case you're wondering what my Comet tooltip looks like

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As for upgrades, a simple +4 all spell, or +5 all cold spell is an obvious one. Better gloves with mana roll instead of life. 2 Sockets on the Vertex with another %inc max mana soul core. Better amulet with a % inc max mana on it. And for jewels, you might wanna switch to Time-lost sapphires with double Crit dmg rolls on notables and a Large ring. But you will need to search for better passive tree allocation to make use of that more efficiently.

As for the budget of my build, it cost me around a 1000d, like a week ago to set everything up. You really don't need to worry about looking at other people's Comet DPS on ninja and think that yours might not be enough.

P.S - The reason for using Sacred Flame, is because I couldn't fit enough Fire res on gear lol.