Use Element Reactions
How To Destroy Shields
Use Element Reactions
Superconduct
Cryo + 
Electro
Superconduct Reactions that deals with AoE Cryo damage that will decrease the Physical RES by 40% for 12 seconds.
Overload
Pyro + Electro
Overloaded, managing Pyro harm around there. Can push back the chief and stop a portion of its Electro Attack. This reaction causes an AoE explosion that deals Pyro. Both the damage done to the reaction target and the AoE damage effect have the same value.
Freeze
Cryo + 
Hydro
Feezes the adversary and make them inactive until further notice.
Recommended Characters
Ganyu
Diona
Chongyun
Bennett
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Characters with safeguard/shield are likewise suggested as they will ensure you for the steady charge harm delivered by the Abyss Lector.
Use A Crowd Control Character
A character with a group control expertise is likewise suggested. This expertise will give you an opportunity to effectively accumulate both and freeze them while giving steady harm.
Tricks
Drag Both Boss Along the edge Of The Field
To effectively defeat the boss and eliminate their safeguard/shield, accumulate them at the tip of the field and consistently harm them.
Thundering Fury On Bennett
You can use Bennett and spam his Skill to rapidly demolish the shields of the Abyss Lector. 4 set Thundering Fury will shorten the already short Cooldown of Bennett's skill enabling him to constantly deal Overload against the shielded Abyss Lector. If you have a Bennett, it is recommended to use him against Abyss Lector.
Abyss Lector - Moveset
Electro Lightning
If you get closer to the Abyss lector it will strike you with an electro lightning that will cause a massive hit damage to your character.
Electro Orbs
It summons waves of electro orbs that causes damage and also an electro status that will drain your character's energy upon touching the orb.
Preview video
Gallery - How to destroy abyss lector shield faster