My recent update keeps saying “update requested” and it’s been stuck on it for 3 days now. How can I restart the update?

I forget the order of operations.. whether it does the 'update requested' before or after it downloads..

Try this:

If you to go Settings > General > iPhone Storage and give it a minute to load.. is there an item in the list that says iOS 13.6? If so, delete it. Force Restart your phone (instructions how to do that are in this link --> https://support.apple.com/en-us/HT201412)

Now go to Settings > General > Software Update. Hopefully now it doesn't say Update Requested and you can start the process over again. Make sure you're connected to WiFi. You can also use a computer to do the update if you continue to have trouble

Update your iPhone, iPad, or iPod touch - Apple Support