Hey! It could be the battery that is faulty, i would try to put a new battery in and test it out. If that doesn’t work i would recommend looking at your warranty. You could be unlucky that they will deny you warranty because you already opened the phone.
When you restart the phone does it come up as a notification that Touch-ID is not working? And have you tried with the old screen if touch-ID works? Could be the new screen that has a faulty flex cable for home button.
Did you repair it yourself or did a shop do it for you? The component is propably damaged and needs to be replaced, If the shop repaired it for you they should replace the broken part.