What to do when iPhone 13 isn't recognized by MacBook Pro when backing up?

I tried backing my iPhone up today on my MBP, but it won’t show up that it’s connected. I have no problem with the Photos app acknowledging my phone and uploading some pictures, so I’m not sure what’s wrong. I have the most up to date iTunes for my OS which is 10.12.6 Sierra. My phone is currently running iOS 18.3.1 and this is the first time I’m having this issue.

[Re-Titled by Moderator]

Original Title: Backing up iPhone 13 on early 2011 MBP