I had the same problem until a minute ago and that’s how I found this post. If you have the tools just replace it with a replacement home button (doesnt have to be from apple) it will pass the boot loop and phone will turn on. After it turns on phone will automatically turn on assistive touch right above the actual home button so you can use that instead because home button functionality and touch id wont work. iPhone also displayed a message said something like “Home button needs service” and of course “Unable to activate Touch ID on this Phone” . Good Luck