Stuck on boot loop after upgrading iPhone SE 10.3.3 to 13.3.1 via iTunes
Not sure whether this is the best answer, but as I more or less got my issue ultimately resolved, I'll describe what I did. DFU mode did not prevent a boot-loop, but restore mode did, which I was only able to enter by holding the power and home buttons continuously while it was plugged into my Mac. iTunes then wanted to install the latest version of iOS, and I had to install it by choosing to restore from a backup rather than trying to install it as an upgrade. This worked, and then it restored from my iTunes backup. Eventually it rebooted, which took longer than normal but not more than a few minutes, and iTunes got right to syncing my music and podcasts.

Unfortunately, having to re-download all my apps over my internet connection was not desirable, especially considering that I intentionally did not update certain apps, but this is better than a boot loop.

One hitch that happened was that on the new welcome screen on my phone, it didn't accept my Apple ID login/password, even though it worked initially within iTunes itself. But it let me skip that step and nevertheless seemed to be signed in to iCloud in iOS anyway.