Genshin Impact
Electro Hypostasis, strategies, weak points, and achievements
Defeat Aleph, the Electro Hypostasis found in Cape Oath on the Southeast part of Mondstadt.

Aleph is an Electro Hypostasis that you can fight in Mondstadt, as it is a Boss made out of pure Electro Energy; it is immune to the element; defeating it will reward you with Lightning Prisms and Electro Crystals.
Electro Hypostasis Location

Electro Hypostasis Arena

Weak Point
This Boss does not have any weaknesses nor weak points, but it is only invulnerable to Electro, so all its other resistances are equal; technically, the elemental and physical resistance is the same overall, but being a pure Electro being, you'll be able to do plenty of elemental reactions with Cryo, Dendro, or Pyro.
Strategy
The Electro Hypostasis is open to your attacks during or right after it ends its attacks. Observe and pick carefully which moments are more accessible for you to attack.
Some of Aleph's Attacks will end up creating some distance between the both of you, so you should have a ranged character for this fight.
If the battle takes too long, the Electro Hypostasis will trap you inside some Electro Pillars with barriers between them; you can escape by attacking one of the Pillars with Cryo, Dendro, or Pyro.
At the end of the fight, Aleph will summon three Electro Prisms, which after a few seconds will heal some of its health; these are weak to Cryo, Dendro, or Pyro attacks, and each takes three hits before being destroyed; destroy all three and the fight is over.
Achievements
The PRISM Program
Break all of an Electro Hypostasis' Revival Prisms before it can be revived.
You have to be fast and use Cryo, Dendro, or Pyro characters that can deal three Elemental attacks consecutively, like a Catalyst character or a Bow user with multiple charges.
Force Field Erosion
Destroy the Electro Hypostasis' barrier.
When the Boss cages you with the Electro Pillars, destroy one of them with elemental reactions, the whole thing will fall, and you'll receive the achievement.
"...Lizard-Spock"
Have one character get hit by all three parts of the rock-paper-scissors attack consecutively.
There is one attack where the Electro Hypostasis will hit you with a Fist, then with Scissors, and lastly, a slap to the ground; if you get hit with all three, you get the achievement; you can see in the ground where the hits will land, so try to adjust if you fall outside the area.
...And Still Smiling!
Defeat an Electro Hypostasis in Co-Op Mode.