I have the regular iPhone 11. I didn’t have to log into iTunes on my computer afterwards but doing the quick volume button up, quick volume down, push and hold the power button (felt like forever) it shut down and then started back up. My phone was on the charger when it was doing the upgrade to 13.1.2 and it sat on the swirling screen for 3 hrs before I panicked, grabbed a different phone, searched online, found this article, and did the force shut off. Just pushing and holding the power and down volume button did nothing. When I go into settings to see if the update worked, it shows that 13.1.2 is available to download and install. Um.... won’t be trying that again anytime soon. My phone was working fine before trying that update.