can't update iPhone 13 Plus from ios 16.6.1 to iOS 17.2.1

can't update iPhone 13 Plus from ios 16.6.1 to iOS 17.2.1. I have 34.4GB of available space on the phone. I did a 'reboot' of the phone. (vol. up, vol. dwn, then hold on/off button until phone shuts down and continue to hold until appl logo apears). I keep the phone plugged into power. I've tried using my cellular data. I've tried using a good wifi connection. Update downloads, verifies, shuts down, apple logo appears with white progress bar at the bottom. Progress moves along fine. I let it sit a bit. When I check phone it's at the manual login screen. I manually log in. The phone opens, and its still showing ios 16.6.1. I've tried multiple times. I also have 'Download iOS Updates', 'Install iOS Updates', and 'Security Responses & System Files' are all toggled on.