iPhone 8 Plus NOT UPDATING/RESTORING

I previously updated my phone to 15.0.2 and then it said that software update 15.1 was available. When I connected it to my Mac it showed that it was downloading the software to my phone. It would then disconnect on its own and show my phone was downloading. It gets stuck at downloading and won't respond after that so I try to begin the restoring/updating process all over. This is frustrating when I have been an Apple user for a very long time and how updating the software causes the phone to malfunction. Is quality a priority anymore these days on these phones?