Cannot update iPhone iOS - both phone and iTunes are getting stuck

I have an iPhone SE. I'm trying to update to 12.3.1. On the phone it is stuck on the message "update requested...". It was like this all day yesterday. Today it reverted back to allowing me to download and install, but after choosing that option, it went back to being stuck (we are going on about an hour now).

I have done the type of reset where one holds down the power button and home button until reset twice. Nothing changed. I've tried using different wifi sources, and again it didn't change anything.

I did try to update through iTunes as well. I am on the most recent version of iTunes. I was able to backup my phone to iTunes, it asked me to continue with update, put in my passcode, and accepted the terms of service. Then it too got stuck on the download page saying "iTunes is downloading a software update for this iPhone and will install it when download is complete." (again, have spent hours like this)

Is there another way to get the update to my phone? i really need to do this update soon. Apple's planned obsolescence with iOS tends to play out as my battery dying immediately when the phone isn't plugged in. So I'm constantly charging this thing (this happens every time I need to update the iOS and fixes as soon as I update. I just want to do the update!).