Chosen Solution
Screen replaced but the home button lost all functionality. It is the original equipment from the original iPhone 8. Help?
You would need to check your home button flex cable first, the one that is attached to the screen. Look under a magnifying glass to see if there is a slight tear. If it is not the flex cable it will be a component on the home button assembly. This would require a reputable repair shop to fix the problem. The only other solution would be a screen replacement by apple.
The home button may be damaged, use a microscope or something to see if there is any visible damage (such as a tear) in the flex cable. Also make sure that everything was fully connected and “clicked” into place. If it is damaged, then your only other option is a screen replacement by Apple, as every individual home button is paired to each device.
