Question about "Elemental Surge". I'm going crazy..

Hello!

So I got lured into this game on the latest season launch.. Now I'm hooked.
Trying out alot of stuff here and there.
But now I'm stuck with a molten blast build that I think is just way chill and fun.

Trying to get stronger and such, so looking around for similar builds, and upgrades etc.

I found this build https://poe.ninja/poe2/builds/abyss/character/AquaMino-4953/%EC%95%84%EB%A7%88%EC%95%84%EB%A7%88%EB%A7%88%EC%A1%B4?i=14&search=class%3DRitualist

And I'm just going crazy.
HOW does he have "Elemental Surge"?

I can't find this ingame, when I look up the spell everything says its an Amazon Ascendancy thingy.
So how does he have it as a ritualist????

Thank you very big.

ALSO, atm I'm running Olrovasara Torment Club.
Is it more worth to get like +4/5 to attack skills instead of that unique effect? (=