iPhone 7 home button not working after disconnecting the battery

I think it is pretty common for Touch ID to require a power cycle to work. We know that the 7 home button is very sensitive to overtightening the screws at the button plate, and we know that some copy screens have home button flex issues. My guess is that your prior problems were likely the screen like you've concluded, and that this one just needs a power cycle.

Home button was not working when fixed the screen. I went back and lossen the screws and it was working, I turned it off and waited a couple of days to give it to the owner, then when I turned on to test it, it was not working. Help..

My guess is you have unknowingly damaged the flex cable where the plate screws on, they are super easy to tear or just slightly nick. Have you tried a new screen?

I think this issue is most commonly a small tear or Nik in the cables between the phone base and the screen that get torn during movement.

Was this ever solved? I have a problem similar to this. Battery cable disconnected and home not working anymore

I believe its the flex cable on new screens, ive tried 3 different screens and home button still doesn't work, replaced old screen and worked fine, the phone also takes a while to boot with the new screens, assuming this is because its trying to connect with the home button but failing? bought another screen from different company and this worked fine. trying so many different screens can wear out the connector so be careful