There is 2 methods to remove Google account for that model,
Method #1 (FlashTool):
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- Run SP Flash Tool
- Go to Format tab
- Select Manual Format Flash
- Now enter this values
- Begin Address[HEX]: 0x6a00000
- Length[HEX]: 0x100000
- Click on Start
- Plug-in powered off phone to PC
- Wait for the operation to complete
Method #2 (TWRP):
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- Flash TWRP using SPFT
- Copy FRP Script zip to SD Card
- Flash it using the TWRP
Now phone won't ask you about the google account anymore.