Akash

Use iTunes sometime the 3utool got some error and you try to restore by saving user data .That process sometime makes that error.Try full restore on that process the data will no longer acessable. Only the iCloud data you got.

The best way to discharge battery is one 4-5 v LED connect to battery still the LED off .I try on one of the battery very time ago.Hope this process is helpful.

Check the parts near the battery connector. Be sure that battery is charged or connect to battery connector properly.

That is the common issues that on iPhone 7 & 7plus series.That is the issues of audio ic the pin under ic is broken that cause.So simply it`s a hardware job need microsoldring skills.That have other issues shows with that problem.If you don`t have idea on repair this may help you. Speaker greyed out. microphone not working. videos recording stuck. no sound on ear speaker. all have common issues that related on.

Remove charging flex and check most of that cases on iPhone X have such problem throw vibrator circuit shorting on charging flex.

The possible region for that solution in my experience. 1 - Battery must be low charge,you have to use extra power source to power on and check. 2- New charging flex is slightly hard to fix on the connector confirm that properly connected. 3- Remove home button flex and check. 4- Check the battery BSI point might be loose contact.

Put more flux and re-solder with pencil bit iron.

First check the BSI ways or the center pin of the battery connected properly or not.

Open charging flex and power on iPhone and check most have vibrator circuit issues.

The answer is no.If your face id have to work in that cases. 1 - Same IR camera 2- Same front camera 3-Same dot projector 4- Same flood illuminator. By seeing you history that the ribbon is broken means the one parts is gone that can`t be fixed for face id.