This page may be some help (thanks to MrBill3):
If your iPhone won't turn on or is frozen - Apple Support
If you can get back into your phone, so to speak, 9to5Mac reported that Apple released a new version of 17.4.1, but it was only available through a computer. On a Mac, plug the phone into the computer, open a Finder window, and select your iPhone in the side bar. If the side panel isn't showing, go to the View menu and click Show Side Bar. On older Macs you may have to use iTunes, but it is similar. On a Windows computer I believe you either open iTunes or the Apple Devices app, but I'm not familiar with that setup.
Anyway, once you have done that, there should be a "page" for your phone. Choose General from the top row, and there will be a Check for Update button. From there you should be able to update your phone the newer version of 17.4.1.
I updated "over the air" to 17.4.1 and didn't see any problems. But when I saw the article I updated again and my phone went through the whole process, which seems to indicate that this is a different update.
9to5Mac reports that the build number for the over-the-air update is 21E236, but the one through a computer is 21E237.