Updated OEMINFO using tespoint

Hi Sir, Please help to explain me.
There are many
-Kirin970 A8.1_V1
-Kirin970 A8.1_V2
-Kirin970 A8.1_V3
-Kirin970 A8.1_V4
So which one should I choose the right ?

Now my phone is CLT-AL00 DaulSim. Lock Huawei ID.
android : 9
build number: 9.0.0.184(C00E57R1P15) Turbo
Android Sec patch : April 1, 2019

1- is it possible to downgrade to 8.1 ?
2- is it possible convert to CLT-L29 ?
3- which firmware should I choose if it should be converted ?

Please help

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